Research House annual water use study report
Research House Annual Water Use Study Report December 2002November 2003
Published in March 2005
Disclaimer This report is distributed by the Department of Housing and Department of Public Works as an information source only. The State of Queensland (Department of Housing and Department of Public Works) makes no statements, representations or warranties about the accuracy or completeness of any information contained in this report. Despite their best efforts, the State of Queensland (Department of Housing and Department of Public Works) makes no warranties that the information in this report is free from infection by computer viruses or other contamination. The Queensland Government disclaims all responsibility and liability (including, without limitation, liability in negligence) for all expenses, losses, damages, and costs you might incur as a result of the information being inaccurate or incomplete in any way or through any other cause. The Queensland Government does not endorse the companies or products and materials referred to in this report.
Copyright The Queensland Government supports and encourages the dissemination and exchange of information. However, copyright protects this material. The State of Queensland asserts the right to be recognised as author of this material and the right to have its material preserved and not altered. Use of material published by the Department of Housing and Department of Public Works should only be in accordance with the Copyright Act 1968 (Cth). The Built Environment Research Unit, Building Division, Department of Public Works prepared this report on the Research House for the Department of Housing. For more information, visit: The Department of Public Works, Building Division, Built Environment Research Unit, website at: www.build.qld.gov.au The Department of Housing’s Smart Housing website at: www.smarthousing.qld.gov.au
Contents 1.0
Background ........................................................................................................ 4
2.0
Scope ................................................................................................................... 4
3.0
Methodology ...................................................................................................... 6
4.0
Rationale ............................................................................................................. 7
5.0
Water use data and findings .......................................................................... 8
6.0
Discussion........................................................................................................10
7.0
Rockhampton city water use ......................................................................14
8.0
Cost of water saving devices .....................................................................15
9.0
Cost benefit analysis ....................................................................................15
10.0
Conclusion........................................................................................................18
References
...................................................................................................................19
Appendix A ....................................................................................................................21 Appendix B ....................................................................................................................23
Figure 1:
Research House - Total water use
Figure 2:
Research House – Whitegoods water use 2003 pie chart
Figure 3:
Daily water use – Research House compared to Brisbane household column chart
Table 1:
Daily water use – Research House compared to Brisbane household
Table 2:
Waste water reduction at selected outlets
Table 3:
Cost of flow restriction devices
Table 4:
Payback period for water flow restriction devices
1.0
Background
All living things depend on water to survive. It is an essential and scarce resource, but one that too few people use responsibly. Australians live on the driest inhabited continent on earth, yet are the greatest consumers of water worldwide [3]. In 2002, the national average water use for a four-person household was 1250-1400L a day, which is equivalent to 250 to 280 buckets of water consumed per household per day [2]. This consumption is predicted to increase [2,4]. The Queensland Government’s Towards Healthy and Sustainable Housing Research Project is demonstrating and testing ways that water is being conserved in the Research House – a sustainable house situated in Rockhampton [6]. The Research House project involved the design and construction of a family home incorporating the principles of the Department of Housing’s Smart Housing i nitiative. A Smart House is one that incorporates the elements of: Social sustainability: A Smart House has been designed with people in mind. It is safe, secure and universally designed. Environmental sustainability: A Smart House is resource efficient in water, waste and energy. Economic sustainability: A Smart House is cost-efficient over time [7]. For further information about Smart Housing , refer to Appendix A or visit www.smarthousing.qld.gov.au.
2.0
Scope
The Research House project aims to demonstrate practical water savings that can be achieved through water conservation, water efficiency and the capture and re-use of water. These practices include the fitting of water flow restriction devices in the shower, kitchen sink, vanity hand basin and washing machine , and the use of water efficient appliances, products and fittings, and rainwater tanks [12,15,23]. The products and appliances in the Research House are classified under the National Water Conservation Rating and Labelling Scheme as certified by the Water Services Association of Australia (WSAA) [8,21]. This scheme rates appliances according to their level of water efficiency, assigning appliances with an ‘A’ rating on a scale of one to five; the more efficient the product the greater number of ’A’s’ it is given.
No flow restriction devices were installed into the bath tub as users will fill the bath tub to their desired depth regardless of restriction devices being installed.
The specifications for water conservation devices fitted in the Research House were based on the concepts of: • •
Volume fill: refers to when a specified container, such as a jug, dishwasher, washing machine, bath or la undry tub is filled, and the amount of water is limited by the size of the container or the specific purpose of the user; and Volume flow: refers to using water in an efficient manner at the outlet.
Most taps fitted inside a typical household deliver water at uncontrolled flow rates of between 20-30 litres per minute. The Research House is managing this water flow through the use of water flow controls. Further savings are being achieved via the installed water efficient appliances. Below is a summary of the flow restriction devices and water efficient appliances in the Research House. • • • • • • •
Water saving bathroom showers (‘AAA’ water rating) are fitted with flow restriction devices reducing flows to 9L/mini. Vanity taps/mixers are fitted with flow restriction devices reducing flows to 6L/min. The kitchen sink mixer tap is fitted with flow restriction devices reducing flows to 9-12L/min. Toilet suites are fitted with dual flush units of 6L and 3L flushing capacity. An automatic sensor tap is fitted in the powder room. The front loader clothes washer (Westinghouse series mastermind LF708B) (‘AAA’ water rating) is fitted with flow restriction devices (Con-Serv ‘Whisper Wash’), which prevent ‘water hammer’. The dishwasher (Dishlex series Global DX450WA) (‘AAA’ water rating) is fitted with flow restriction devices (Con-Serv ‘Whisper Wash’) restricting water flow to 8L/ min.
An electronic garden sprinkler system with a moisture sensor is efficiently managing water in the garden.
Kitchen tap
Water is also used effectively in the garden through catchment of rainwater in tanks, and planting of low water-demanding plants in landscaping. The tanks are manually operated for gravity feed to the gardens. The rapid hot water response from the hot water heat pump system (Quantum) also saves water. This system works on the principle of refrigeration (reverse cycle), drawing heat out of one space and discharging it into another. Unlike other hot water systems, which have a heat coil at the base, this system has a heating coil that runs the height of the system. This coil allows water to remain at a more consistent temperature throughout the system, rather than hot water being concentrated at the base of the system. This means that hot water is provided more quickly from the system to the outlet, reducing water wastage [15].
3.0
Methodology
Water turbine transducers are installed in 15 locations throughout the Research House to capture data for principal water usage areas in the house. These transducers are measuring water use in the following areas: • • • • • • • •
hot water system powder room toilet powder room vanity ensuite toilet ensuite vanity ensuite shower bath bathroom vanity
• • • • • • •
bathroom shower laundry tub kitchen sink hot/cold drinking water dishwasher clothes washer mains water
Note: A layout showing the location of water sensors is shown in Appendix B. These transducers measure water use via water flow. As water flows through the transducer it causes the turbine blade to rotate. As the blade rotates it intercepts a laser light from the digital optical transmitter, and creates a digital pulse. These pulses are counted each minute by a data logger and converted to a water volume value, which is saved to a text file. The Faculty of Engineering and Physical Systems at Central Queensland University (CQU) in Rockhampton installed the water data collection hardware and software [9]. CQU is logging the data from the water sensors and is working to analyse and present the results in collaboration with the Department of Public Works’ Built Environment Research Unit. Over each quarterly period (summer, autumn, winter and spring), water usage is being tabulated daily, and savings in water consumption are being identified. The annual data collection is showing consistent water usage patterns, so the estimated cost benefits and the water savings are being identified. The hot water usage is being recorded over the four seasons, with the summer and winter seasons being the main focus of analysis. At the end of the current testing period of the heat pump hot water system (Quantum), the house will be retrofitted with an electric boostered solar hot water system (Solahart) and afterwards with an instantaneous gas system (Bosch) [14]. These changes will occur to identify any variations in water use (as well as energy use) between electric, gas and solar powered hot water systems and the outcome of this work will be presented in future water data reports.
4.0
Rationale
Water data is being recorded and water savings are being identified through the use of flow restriction devices. The annual water usage of the Research House tenants will be compared to the water use in an average Brisbane household of four. This particular comparison was chosen as creditable published papers in the public domain are available for Brisbane, whereas there is a shortage of suitable published papers in the public domain for Rockhampton suburban households. Although no detailed water consumption data is available for the average Rockhampton household some comparisons will be made using available data. Note: Please note the daily water use figures are based on 4.67 persons per household (due to the tenant’s third child moving into the Research House in May. The figures have been averaged for 4.67 persons over the year). Therefore, the Brisbane data has been adjusted to a 4.67 person household for the purpose of this comparison. The Brisbane water data was taken from the Brisbane City Council data, which was current at 28 December 2003 and is averaged over the 12 months prior to that date. The water used by the dishwasher (Dishlex) and front-loader clothes washer (Westinghouse) will be benchmarked against the Australian/New Zealand Standard for commonly used ‘AA’ and ‘AAA’ appliances respectively, and Brisbane Water data for appliances [11,12,13,15]. Due to variations in user patterns and the various cycles of the appliances, no comparative analysis will be made against the manufacturers’ published information for water use. Rainwater is being captured and held in two tanks of 2,000L and 5,000L capacity. Use of the tank water is restricted to gardens due to health risks associated with drinking tank water and cost impacts of other re-use options. The tenants manually operate watering from the tanks. The quantity of to wn water saved, and rainwater used, from these tanks Rainwater tank will be calculated and costed, based on tariff charges from various councils in Central and South-East Queensland, to determine values in terms of dollars saved. Ongoing analysis of rainwater captured and used will be made over a further period of time as insufficient water has been used at this stage. The project team is investigating ways of maximising the use of tank water in the future and this will be reported in future water data reports.
5.0
Water use data and findings
Total water use 1 December 2002 – 30 November 2003: 419,512L
Outdoors 51%
Laundry 6%
Kitchen, drinking and cleaning 15%
Showers and bath 18% Toilet flushing 10%
Figure 1: Research House - Total annual water use 2003 Note: The above overall water use Figure 1 for the Research House includes data for whitegoods in the kitchen and laundry segments.
Whitegoods water use 1 December 2002 – 30 November 2003: 29,302L [7%].
Other household use 93%
Washing machine 4%
Hydrotap 1.0%
Dishwasher 2%
Figure 2: Research House – Whitegoods annual water use 2003 Note: The ‘other’ segment in Figure 2 includes all other indoor water used in the Research House apart from whitegoods.
Over the year, the total average daily water consumption for the Research House was 1,150L made up of 49% for indoor use and 51% for gardens, lawns and other outdoor use (Figure 1).
The dishwasher uses approximately 29L and the clothes washer uses 43L of water per day respectively, which is approximately 7 percent of the total water usage of the Research House [12 (figure 2)]. The wet areas, such as the shower and bathrooms, used a total daily average of 211L, which equates to approximately 18% of household water consumption. Shower and bath usage has been combined in line with the Brisbane data. The toilets use an average of 116L a day, which is approximately 10 percent of total household water consumption. Of the total water consumption for the year, 14% was used in cooking, cleaning and drinking, which includes the Zip hydrotap (instant boiling and chilled filtered water dispenser). Tenants usage of the hydrotap averaged 9L a day. The hot wa ter average daily use in the Research House for the year was 129L a day or 11% of the total water use. The outdoor water usage was initially very high in the first two months (October and November 2002) due to the fitting of incorrect sprinklers, which wasted huge quantities of water through over-watering of the gardens and lawns. Installation and calibration of the correct low flow sprinkler heads provided a more efficient watering system. Even with this intervention, outside water use still accounts for a substantial proportion of the households total water use – 588L/day (51%). During the summer period (December 2002 – February 2003), the unfiltered mains inlet for town water interfered with the accuracy of the water sensors. The fine dirt particles in the town water supply slowed down the turbine motion of the transducers giving low water flow readings. As a result the reading for total outdoor water use during summer 2002-2003 is suspected to be lower than actual use. An inline fine filter was installed at the mains inlet for the house. The pattern of water usage became more consistent during the second half of the year (winter and spring seasons), giving further confidence that the transducers were giving an acceptable degree of accuracy in the readings.
6.0
Discussion
6.1
Outcome overview Table 1: Daily water use table – The Research House compared to a Brisbane city household averaged over the year [5,10,22] Daily average water consumption 2002- 2003 Area Outdoors Showers and bath Toilet flushing Laundry tub Kitchen sink and cleaning Clothes washer Dishwasher Drink dispenser Total household
Research House 588L 211L 116L 26L 128L 43L 29L 9L 1,150L
Brisbane City 668L 350L 130L 30L 140L 80L 45L 12L 1,455L
Table 1 shows the total daily water consumption for the Research House is 1,150L and the annual water consumption is 419,512 litres. An average Brisbane family uses 1,455L per day or 531,075 litres per year. The percentage of this water used indoors and outdoors is similar between the two households [5,10,22]. Even with a metered sprinkler system, moisture sensors and tank water available, the Research House still uses an average of 588L per day on the gardens. Although this is 100L per day (or 36,500 litres per year) less than the average Brisbane household, it suggests that there are further opportunities to save water by reducing water use outdoors.
Figure 3: Daily water use chart – Research House compared to Brisbane household (figures adjusted to 4.67 person household) Daily Average Water Usage
Average Daily Use (Litres)
700 600
668 588
Brisbane City 500 Research House 400 350
300 211
200 130
140 128
116
100 30 26
80
43
45
29
12
9
0 rs g h her Tub her ing hin Bat doo dry was was ean lus l s& n h Out F r c s s u t i e e D le w La th k& Toi Clo Sho Sin en h c t Ki Usage
g kin Drin
Note: Consumer patterns would influence the amount of water used or saved. Longer showers, full baths, garden sprinkling times will have dramatic impacts on water used in a household.
6.2
Outdoors
In the year, the Research House used 214,620 litres of water for outdoor use. Figure 3 shows a little over 80L of water per day have been saved outdoors. Further studies will be undertaken to look at ways of reducing this water usage. This will be documented in future water data reports.
6.3
Shower and bath
The water consumption in the shower and bath is influenced by user patterns as well as the flow control rate (9 litres per minute) of the water efficient showerheads. When compared to Brisbane household figures (figure 3 refers), the ‘wet areas’ of the Research House, such as the shower and bathrooms, are using approximately 139L or 40% less water per day. This can be attributed to the water saving devices (flow restrictors and efficient shower heads) and the highly efficient heat pump hot water system [15]. It is known that showers are the preferred option for the Research House tenants where as the preference is unknown for the Brisbane household. Water saving Table 1 shows that the tenants’ water use pattern in the Research House for the shower and bath resulted in an average water consumption of 16,490 litres per person per year. In comparison, the average water consumption in a typical Brisbane household is 27,355 litres per person per year. The approximate average yearly water saving is 10,865 litres per person.
Table 1 also shows that in the Research House, the use of an efficient showerhead with a maximum flow rate of 9 litres per minute (9L/min) has the potential to save approximately 20,000 litres of water per person per year (20,000L/pp/y). This is in comparison to a standard showerhead of 20L/min based on the same user time per person per year as in the Research House. The average shower times in the Research House are between five to eight minutes. With standard flow rates being up to 20L/minute, water efficient showerheads at 9L/minute can potentially save up to 11L/minute. With average shower times being between 5 to 8 minutes, this equates to potential water savings of between 55 to 88 litres of water per shower. Hot water The amount of hot water used depends on the duration of the shower, the flow rate of the water-saving showerhead or the quantity of water in the bath, the type of water heater installed and as does the pattern of use. Research House tenants’ household with the heat pump hot water system (Quantum) used an average of approximately 129L per day. By comparison a typical Brisbane household with a 315L off-peak electric storage system used an average of approximately 140L a day. Accordingly, Research House has achieved annual hot water saving of around 4015L or 8.0% less than the conventional electric storage system. The shower and bath area alone can realise total water (hot and cold) savings of at least 139L a day or 50,700 litres over a year [11,15]. A higher efficient (litres/kilowatt hour) hot water system, heats a larger volume of water (litres) for the equivalent units of energy consumed (kWh). The quicker recovery period and the efficient conduction of heat into the stored water for the heat pump water heater (Quantum) means the stored hot water stays at a higher temperature over a longer period, with the benefit that less hot water is used in the Research House.
6.4
Toilet flushing
The data for toilet flushing shows that 14L/day or 5,110L/year are saved at the Research House through the installation of dual flush systems, in comparison to a similar Brisbane household.
6.5
Laundry tub
The Research House laundry tub tap realises a 4L/day saving or 1460L/year whe n compared to a Brisbane household.
6.6
Kitchen sink and cleaning
The kitchen, cleaning and drinking water accounts for 12L/day saving which is an additional 4380L/year compared to a Brisbane household.
6.7
Dishwasher and clothes washer
The dishwasher and clothes washer in the Research House with their higher water conservation ratings have achieved water savings of 16L/day and 37L/day respectively. The selected dishwasher (Dishlex) (‘AAA’ water rating) and clothes washer (Westinghouse)(‘AAA’ water rating) appliances installed in the Research House are delivering water savings of at least 40% over commonly used household
appliances in Brisbane which have a ‘AA’ water conservation rating. Standard clothes washers and standard dishwashers are usually classified as AA-rated. The (‘AAA’ water rated) dishwasher in the Research House uses on average 30L per load, whilst a typical Brisbane household dishwasher (‘AA’ water rating) uses around 45L per load. As most dishwashers are used once on a daily basis this equates to an annual saving of 5,475 litres of water. The front loader clothes washer (‘AAA’ water rating) in the Research House uses an average 45L per load while a typical Brisbane household top loader clothes washer (‘AA’ water rating) uses around 80L per load [8,12]. The front loader clothes washer at the Research House has a water volume selection panel, which enables the operator to choose to use less water. Tenant feedback confirms that this option is regularly chosen. Annual water savings of 12,775L have been calculated when compared to standard ‘AA’ rated top loader clothes washers. The selection of water efficient appliances in the Research House, such as the dishwasher and clothes washer, indicates that consumers could save approximately 18,250L (18.25kL) of water per annum respectively [7].
6.8
Waste water production and reduction
Table 2 , below, shows that the total waste water discharge to the sewer in the Research House is 201,848L per year (not including water use from the hot/cold drink dispenser). Table 2 also shows that based on a standard mean maximum flow rate of 20 litres per minute (20L/min), a 55% reduction in waste water of 246,704L is achieved through the use of flow restriction devices and ‘AAA’ rated appliances in the Research House. This waste reduction has major infrastructure impacts as council has less waste water to treat and dispose of. The environment will also benefit from having less waste water being treated and released. Table 2: Total indoor waste water production for fixed maximum flow rates Outlet Kitchen sink (grey) Bathroom shower (grey) Ensuite shower (grey) Toilet (black) Ensuite toilet (black) Clothes washer (grey) Bathroom vanity (grey) Dish washer (grey) Laundry tub (grey) Ensuite vanity (grey) Bath tub (grey) Total Waste Water
Research House 9L/Min 46,720 29,795 27,043 25,780 16,563 15,695 13,012 10,584 9,490 6,269 897 201,848
Standard 20L/Min 103,822 66,211 60,096 57,289 36,807 34,878 28,916 23,520 21,089 13,931 1,993 448,552
30L/Min 155,733 99,317 90,143 85,933 55,210 52,317 43,373 35,280 31,633 20,897 2,990 672,826
Table 2 Notes: (1) Waste water at the Research House is based on actual use at a mean maximum flow rate of 9 litres per minute (9L/min). (2) Waste water reduction at a mean maximum flow rate of 20 litres per minute (20L/min) and 30L/min is a comparison to the Research House actual waste water at a mean maximum flow rate of 9L/min.
(3) Total waste water (201,848L) use does not include the hot/cold drink dispenser (3,282L). (4) Table 2 does not include outside water use.
7.0
Rockhampton city water use
Although no detailed water consumption data is available for the average Rockhampton household, the following comparison can be made from available data. The average residential water consumption in Rockhampton, for a family of 2.61 persons per household is 538,000L (538kL) per annum or 206,130L per person per annum (Widt, Aitken and Artemieff [22]), which equates to an approximate average daily use of 565L per person. The Research House consumed 420,000L per annum for a family of 4.67 persons per household or an approximate average daily use of 246L per person. Using reference data from this source, the Research House uses approximately 319L less per person per day or approximately 116,000L less water per person for the year compared to an average Rockhampton household per person. Using this as the basis of calculation, it is estimated that the Research House (4.67 persons per household) used a total of 543,752L of water less than a Rockhampton household with the same number of people (4.67).
8.0 Cost of water saving devices The installed cost of the total water saving devices in the Research House (which also provide a totally balanced, pressurised water system) is $316.00 (installed December 2002). Note: This cost is specific to the Research House and is an example only of the installed cost of the devices in a new home. Table 3 below provides a break-up of the total purchase cost only of the water saving flow restriction devices in the Research House.
Table 3: Costs of flow restriction devices Item description Qty Shower rose at 9 litres per minute (flow restriction) 2 Vanity basin at 6 litres per minute (flow restriction) 3 Kitchen sink at 12 litres per minute (flow restriction) 1 Laundry tub at 12 litres per minute (flow restriction) 1 Dishwasher/clothes washer back-flow prevention valves 2 (whisper wash) External taps back-flow prevention values 2 Total retail cost (excludes installation)
Rate ($) 23.00 19.00 26.00 20.00 27.00
Amount ($) 46.00 57.00 26.00 20.00 54.00
20.00
40.00 $243.00
Table 3 Notes: (1) Installation cost is estimated to be $73.00 in a new house at time of construction. (2) Hand held shower (Con-Serv pulsator colour chrome) with wall mount bracket and switch-cock provided in the Research House is around $210.00 recommended retail price (GST inclusive).
For more information on the pay back period of the water saving devices see Cost Benefit Analysis (section 9.0).
9.0 Cost benefit analysis Cost benefit analysis (CBA) is a technique used in the decision-making process to determine whether a cost outlay over time is a worthwhile investment. The cost (capital outlay) can be either a one-off or it may be incurred over time. The costs of the water flow restriction devices (table 3) in the Research House are a one-off cost outlay. The benefits (savings) are most often gained over time and the time it takes to recover the initial capital outlay (costs) can be assessed in the analysis by calculating a payback period. The benefits of the installed water flow restriction devices in the Research House are the cost savings made in terms of water conservation and energy conservation (hot water system). The Research House uses approximately 111,000L less water per year compared to that of a typical Brisbane household [6,8,10,15]. This means that Brisbane consumers could potentially save approximately $20.00 per annum per person on their water bill by utilising the water saving strategies adopted in the Research House. This figure has been calculated based upon Brisbane City Council two-part tariff charge of 84 cents flat rate for every kilolitre (kL) of water used plus a water access charge of $100.00 for each household. Brisbane City Council has a ‘water use cost calculator’ on their web site www.ourbrisbane.com [24] as a service to Brisbane City ratepayers, in order to calculate their mean quarterly or yearly water use cost [10,25].
By comparison, Rockhampton consumers could potentially save approximately $55.00 per annum per person on their water bill by utilising the water saving strategies adopted in the Research House. Table 3 shows the total retail cost of the water flow restriction devices is $243.00 and the estimated installation cost is around $73.00, giving a total installed cost of $316.00 for the Research House. The estimated potential savings for a Brisbane household on their water bill is $20.00 per annum per person or around $80.00 per household (4person household) per annum. The payback period calculates whether the installed costs of the water flow restriction devices are a worthwhile investment.
Table 4 below shows the calculated pay back period to recover the installed cost of the water flow restriction devices in a typical Brisbane household (based on 2003 costs). Table 4 – Payback period for water flow restriction devices (Brisbane household)
Payback period (T) Costs ($)
Savings ($)
Pay-back (years)
$316.00
$80.00
4.0
Table 4 Notes: (1) Installed cost will vary geographically within Queensland subject to transport cost and labour costs and normal market supply and demand for the devices. (2) Energy cost for water heating is not included in calculations in Table 4. However, it is estimated an additional $40.00 per Brisbane household per year is saved in reduced hot water electricity cost. The payback period (Brisbane household) will be reduced to 2.6 years when electricity water heating costs are included.
In comparison, using the formula in Table 4 for a typical Rockhampton household (4 person household), the pay back period to recover the installed cost of the water flow restriction devices is only 1.5 years. In summary, it can be concluded that the average payback period for a typical Brisbane household is approximately fo ur years, while the payback period for Central Queensland regions (Rockhampton) based on the water use in the Research House is 1.5 years. This figure has been calculated based upon the new two part user pays tariff introduced from 1 July 2004 by Fitzroy River Water, Rockhampton. The new charges are 47.5 cents per kilolitre (kL) for the first 500 kilolitre (kL) and 97 cents per kilolitre (kL) for all additional usage of water used plus a water access charge of $212.00 per annum for each household.
10.0 Conclusion Analysis of data from the Research House in comparison to the average Brisbane household confirms that significant water savings can be achieved for minimal cost outlay. Flow restriction devices to taps and showers offer real water savings for little up front cost, particularly if installed at time of construction. Dual flush (full/half flush) toilets also provide the opportunity for real water savings. Water efficient appliances – the ‘AAA’ rated clothes washer and ‘AAA’ rated dishwasher - are delivering water savings in comparison to similar but lesser rated appliances in the typical Brisbane household. The option to select the water volume in the clothes washer offers even greater water saving potential. With garden and outdoor water use being approximately 51% of the total water use at the Research House (the remaining 49% used indoors with water restriction devices) there are further opportunities to save significant volumes of water. This will be investigated and other options will be trialled to try to reduce outdoor water use without compromising the lawn or other vegetation. The use of rainwa ter tanks to collect and re-use rainwater may require further supporting technology to maximise the use of water collected. Initially minimal water re-use has been achieved with the manual drip feed supply to the gardens currently in place. This will be investigated further in future testing at the Research House. The Research House has reduced its waste water discharge by in excess of 100,000 litres per year through the use of water restriction devices and technology in conjunction with the current tenants’ usage patterns. This will be monitored in future studies and reported accordingly. Study of water use in the Research House has shown there is the potential for broad scale water savings to be achieved through households adopting ‘WaterWise’ strategies. This would mean significant benefits for Australia’s water supply and councils in treating and disposing of waste water. With increased water rates and tariffs, water saving in our homes can save consumers money and will have a positive impact on the environment. As well as water savings, proven energy savings through the use of more energy efficient products like the water heater (Quantum heat pump), dishwasher (Dishlex), clothes washer (Westinghouse) and refrigerator (Westinghouse) are deliverable outcomes. The Energy Use Study Annual Report 2002 – 2003 (by the Queensland Department of Public Works, Building Division, Built Environment Research Unit) provides more detail on the energy savings in the Research House. For more information on the Research House, visit www.smarthousing.qld.gov.au.
References Australian Greenhouse Office, Energy Efficient Appliance, [online], Available from: http://www.energyrating.gov.au/productmenu.html [3 February 2004] [16] Australian Greenhouse Office, Good Residential Design Guide Your Home –Water Use Introduction, [online], Available from: http://www.greenhouse.gov.au/yourhome/technical/fs20.htm [3 February 2004] [17] Australian Greenhouse Office, Greenhouse Gas (GHG) Emissions, [online], Available from: http://www.greenhouse.gov.au/coolcommunities/strategic/ [3 February 2004] [18] Australian Bureau of Statistics, Environment Rivers, inland waters and groundwater (water use), [online], Available from: http://www.abs.gov.au/CA25670D007E9EA1/0/AC692937B0A5A313CA2569E700146DED?Op en [3 February 2004] [20] Australian Standards, AS/NZS6400: 2003, Water Efficient Products –Ratings and Labelling, [online], Available from: http://www.standards.com.au/catalogue/script/Result.asp?PSearch=false&SearchType=simple &Db=AS&Degn=6400&Keyword=&Search=Search&Max=15 [3 February 2004] [21] Brisbane City Council, Water Conservation –Average Household Water Usage, [online], Available from: www.brisbane.qld.gov.au/BCC:STANDARD:1771298931:pc=PC_922 February 2004] [10] Brisbane City Council, Water Usage Patterns, [online], Available from: www.brisbane.qld.gov.au/BCC:STANDARD:1771298931:pc=PC_912# [May 2004] [24] Brisbane City Council, Water Cost Estimates , [online], Available from: www.brisbane.qld.gov.au/BCC:STANDARD:1771298931:pc=PC_912# [May 2004] [25] Central Queensland University, Faculty of Engineering and Physical Systems, Research House, [online], Available from: http://www.engineering.cqu.edu.au/researchhouse/ [3 February 2004] [9] Bosch Australia, Gas Hot Water, [online], Available from: http://www.bosch.com.au/content/language1/html/1708.htm [3 February 2004]. [14] CSIRO Sustainable Ecosystems, Australian Water Use Statistics Report ? on Australian Water Futures, [online], Available from: http://www.cse.csiro.au/research/Program5/publications/0103f.pdf [3 February 2004 [5] Con-Serv, Flow Restrictions Devices and Water Saving Shower Heads, [online], Available from: www.con-serv.com.au [3 February 2004]. [23] Department of Environment and Heritage, Domestic Water Consumption, [online], Available from: Department of Environment and Heritage [3 February 2004] [4]
Department of Housing, Research House, [online] Available from: http://www.housing.qld.gov.au/builders/research_house/index.htm [3 February 2004] [6]
Department of Housing, Smart Housing, [online], Available from: http://www.housing.qld.gov.au/builders/smart_housing/ [3 February 2004] [7] Department of Housing, (August 2002), Research House Flyer, [online], Available from: [4 February 2004] [26] Dr Peterson, L., E., (June 2003) Hot Water Systems Report, Queensland Department of Public Works, Building Division, p. 1-18. [11] Electrolux Australia, Whitegoods Products, [online], Available from: http://www.electrolux.com.au/node139.asp [3 February 2004] [12] Natural Resources and Mines, International Year of Fresh Water – Domestic Consumption. Quantum Energy Technologies, Energy Efficient Hot Water, [online], Available from: http://www.quantumhotwater.com/ [3 February 2004] [15] Rocky Mountain Institute, Water, [online] [1] Available from: http://www.rmi.org/sitepages/pid15.php [3 February 2004]. Rocky Mountain Institute, Commercial, Industrial and Institutional Water Efficiency, [online], Available from: http://www.rmi.org/sitepages/pid276.php [3 February 2004]. [27] Save Water, Water Conservation –Why Save Water? [online] Available from: http://www.savewater.com.au/default.asp?SectionId=5&ContentId=131&Page=2&SortTag=269 [3 February 2004] [3] Sustainable Energy Authority Victoria, (2002), Energy Smart Housing Manual, [online], Available from: http://www.seav.vic.gov.au/ftp/buildings/5starhousing/ESHousingManualCh09.pdf [4 February 2004] [19] Water Services Association of Australia, The National Water Conservation Rating and Labelling Scheme, [online], Available from: http://www.wsaa.asn.au/frames et2.html [3 February 2004] [8] Widt J., Aitken K., Artemieff. P., (October 1999), Water Utilities Queensland Report 1997/98, Department of Natural Resources, p. 1- 56. [22] Zip Industries Australia, Hydroboil, [online], Available from: http://www.zipindustries.com/?p=1730 [3 February 2004] [13]
Appendix A What is Smart Housing? Smart Housing is simple, common sense housing design. The Department of Housing's Smart Housing initiative aims to help Queenslanders to plan and build homes that are more sustainable over time. A Smart House is liveable, safe, secure, costefficient and environmentally-friendly. What is a Smart House? A Smart House is more socially, environmentally and economically sustainable. Social sustainability A Smart House has been designed with people in mind: Safety Safety is about preventing injuries in and around the home. Features such as reduced-slip flooring, a lockable cabinet for storing poisons and medicine, and ensuring that the kitchen is not also a passageway can improve safety in the home. Security Security is about using design and fixtures or fittings to reduce crime. Security screens on doors and windows, adequate lighting of all doors that open to the outside, and being able to observe the neighbourhood from inside the home will improve security. Universal design A universally designed home is flexible and comfortable for people with varying abilities and at different stages in their lives. Universal design is about your home working for you - now and in the future. This means having wide hallways and doorways, level entries to the house and main living areas, and at least one bathroom/toilet and one bedroom accessible for a person with restricted mobility.
Environmental sustainability A Smart House is resource efficient. A Smart House will reduce environmental impacts through efficient use of water and energy resources and careful selection of materials to reduce waste [6]. Water efficiency You can achieve water efficiency by choosing water saving showers and taps and consider using water tanks for watering the garden and flushing the toilet.
Water efficiency can bring other benefits besides reduced water bills. Some of these benefits are: • • • •
Energy savings – heating, pumping and treatment of water is reduced; Water service facility investment reduction; Environmental benefits – more water available for local streams, wetlands and the ecology; and Higher worker productivity – worker productivity and service quality may be higher due to a lower absenteeism [27].
Waste efficiency Careful design and planning can save materials being wasted during initial construction. It may also reduce the need for expensive modifications as the occupants’ needs change. Energy efficiency Passive solar design features such as house orientation, ventilation, insulation and adequate shading can improve energy efficiency. In many cases, it is possible to keep the interior of the home cool in summer and warm in winter without resorting to artificial heating and cooling devices. Economic sustainability A smart house is cost-efficient over time. This means smart features are included in the initial design and construction, reducing the cost of changes and modifications in the future. Altering an existing home to accommodate changing lifestyles can cost up to three times more than including the same features in the initial design and build stage. Using materials with low long-term maintenance costs will save money over the life of the house. Installing appliances with high energy-star ratings will also reduce ongoing expenses. Smart Housing may even increase the resale value of your home because it meets the needs of a wider range of people.
Appendix B
Published in March 2005
Disclaimer This report is distributed by the Department of Housing and Department of Public Works as an information source only. The State of Queensland (Department of Housing and Department of Public Works) makes no statements, representations or warranties about the accuracy or completeness of any information contained in this report. Despite their best efforts, the State of Queensland (Department of Housing and Department of Public Works) makes no warranties that the information in this report is free from infection by computer viruses or other contamination. The Queensland Government disclaims all responsibility and liability (including, without limitation, liability in negligence) for all expenses, losses, damages, and costs you might incur as a result of the information being inaccurate or incomplete in any way or through any other cause. The Queensland Government does not endorse the companies or products and materials referred to in this report.
Copyright The Queensland Government supports and encourages the dissemination and exchange of information. However, copyright protects this material. The State of Queensland asserts the right to be recognised as author of this material and the right to have its material preserved and not altered. Use of material published by the Department of Housing and Department of Public Works should only be in accordance with the Copyright Act 1968 (Cth). The Built Environment Research Unit, Building Division, Department of Public Works prepared this report on the Research House for the Department of Housing. For more information, visit: The Department of Public Works, Building Division, Built Environment Research Unit, website at: www.build.qld.gov.au The Department of Housing’s Smart Housing website at: www.smarthousing.qld.gov.au
Contents 1.0
Background ........................................................................................................ 4
2.0
Scope ................................................................................................................... 4
3.0
Methodology ...................................................................................................... 6
4.0
Rationale ............................................................................................................. 7
5.0
Water use data and findings .......................................................................... 8
6.0
Discussion........................................................................................................10
7.0
Rockhampton city water use ......................................................................14
8.0
Cost of water saving devices .....................................................................15
9.0
Cost benefit analysis ....................................................................................15
10.0
Conclusion........................................................................................................18
References
...................................................................................................................19
Appendix A ....................................................................................................................21 Appendix B ....................................................................................................................23
Figure 1:
Research House - Total water use
Figure 2:
Research House – Whitegoods water use 2003 pie chart
Figure 3:
Daily water use – Research House compared to Brisbane household column chart
Table 1:
Daily water use – Research House compared to Brisbane household
Table 2:
Waste water reduction at selected outlets
Table 3:
Cost of flow restriction devices
Table 4:
Payback period for water flow restriction devices
1.0
Background
All living things depend on water to survive. It is an essential and scarce resource, but one that too few people use responsibly. Australians live on the driest inhabited continent on earth, yet are the greatest consumers of water worldwide [3]. In 2002, the national average water use for a four-person household was 1250-1400L a day, which is equivalent to 250 to 280 buckets of water consumed per household per day [2]. This consumption is predicted to increase [2,4]. The Queensland Government’s Towards Healthy and Sustainable Housing Research Project is demonstrating and testing ways that water is being conserved in the Research House – a sustainable house situated in Rockhampton [6]. The Research House project involved the design and construction of a family home incorporating the principles of the Department of Housing’s Smart Housing i nitiative. A Smart House is one that incorporates the elements of: Social sustainability: A Smart House has been designed with people in mind. It is safe, secure and universally designed. Environmental sustainability: A Smart House is resource efficient in water, waste and energy. Economic sustainability: A Smart House is cost-efficient over time [7]. For further information about Smart Housing , refer to Appendix A or visit www.smarthousing.qld.gov.au.
2.0
Scope
The Research House project aims to demonstrate practical water savings that can be achieved through water conservation, water efficiency and the capture and re-use of water. These practices include the fitting of water flow restriction devices in the shower, kitchen sink, vanity hand basin and washing machine , and the use of water efficient appliances, products and fittings, and rainwater tanks [12,15,23]. The products and appliances in the Research House are classified under the National Water Conservation Rating and Labelling Scheme as certified by the Water Services Association of Australia (WSAA) [8,21]. This scheme rates appliances according to their level of water efficiency, assigning appliances with an ‘A’ rating on a scale of one to five; the more efficient the product the greater number of ’A’s’ it is given.
No flow restriction devices were installed into the bath tub as users will fill the bath tub to their desired depth regardless of restriction devices being installed.
The specifications for water conservation devices fitted in the Research House were based on the concepts of: • •
Volume fill: refers to when a specified container, such as a jug, dishwasher, washing machine, bath or la undry tub is filled, and the amount of water is limited by the size of the container or the specific purpose of the user; and Volume flow: refers to using water in an efficient manner at the outlet.
Most taps fitted inside a typical household deliver water at uncontrolled flow rates of between 20-30 litres per minute. The Research House is managing this water flow through the use of water flow controls. Further savings are being achieved via the installed water efficient appliances. Below is a summary of the flow restriction devices and water efficient appliances in the Research House. • • • • • • •
Water saving bathroom showers (‘AAA’ water rating) are fitted with flow restriction devices reducing flows to 9L/mini. Vanity taps/mixers are fitted with flow restriction devices reducing flows to 6L/min. The kitchen sink mixer tap is fitted with flow restriction devices reducing flows to 9-12L/min. Toilet suites are fitted with dual flush units of 6L and 3L flushing capacity. An automatic sensor tap is fitted in the powder room. The front loader clothes washer (Westinghouse series mastermind LF708B) (‘AAA’ water rating) is fitted with flow restriction devices (Con-Serv ‘Whisper Wash’), which prevent ‘water hammer’. The dishwasher (Dishlex series Global DX450WA) (‘AAA’ water rating) is fitted with flow restriction devices (Con-Serv ‘Whisper Wash’) restricting water flow to 8L/ min.
An electronic garden sprinkler system with a moisture sensor is efficiently managing water in the garden.
Kitchen tap
Water is also used effectively in the garden through catchment of rainwater in tanks, and planting of low water-demanding plants in landscaping. The tanks are manually operated for gravity feed to the gardens. The rapid hot water response from the hot water heat pump system (Quantum) also saves water. This system works on the principle of refrigeration (reverse cycle), drawing heat out of one space and discharging it into another. Unlike other hot water systems, which have a heat coil at the base, this system has a heating coil that runs the height of the system. This coil allows water to remain at a more consistent temperature throughout the system, rather than hot water being concentrated at the base of the system. This means that hot water is provided more quickly from the system to the outlet, reducing water wastage [15].
3.0
Methodology
Water turbine transducers are installed in 15 locations throughout the Research House to capture data for principal water usage areas in the house. These transducers are measuring water use in the following areas: • • • • • • • •
hot water system powder room toilet powder room vanity ensuite toilet ensuite vanity ensuite shower bath bathroom vanity
• • • • • • •
bathroom shower laundry tub kitchen sink hot/cold drinking water dishwasher clothes washer mains water
Note: A layout showing the location of water sensors is shown in Appendix B. These transducers measure water use via water flow. As water flows through the transducer it causes the turbine blade to rotate. As the blade rotates it intercepts a laser light from the digital optical transmitter, and creates a digital pulse. These pulses are counted each minute by a data logger and converted to a water volume value, which is saved to a text file. The Faculty of Engineering and Physical Systems at Central Queensland University (CQU) in Rockhampton installed the water data collection hardware and software [9]. CQU is logging the data from the water sensors and is working to analyse and present the results in collaboration with the Department of Public Works’ Built Environment Research Unit. Over each quarterly period (summer, autumn, winter and spring), water usage is being tabulated daily, and savings in water consumption are being identified. The annual data collection is showing consistent water usage patterns, so the estimated cost benefits and the water savings are being identified. The hot water usage is being recorded over the four seasons, with the summer and winter seasons being the main focus of analysis. At the end of the current testing period of the heat pump hot water system (Quantum), the house will be retrofitted with an electric boostered solar hot water system (Solahart) and afterwards with an instantaneous gas system (Bosch) [14]. These changes will occur to identify any variations in water use (as well as energy use) between electric, gas and solar powered hot water systems and the outcome of this work will be presented in future water data reports.
4.0
Rationale
Water data is being recorded and water savings are being identified through the use of flow restriction devices. The annual water usage of the Research House tenants will be compared to the water use in an average Brisbane household of four. This particular comparison was chosen as creditable published papers in the public domain are available for Brisbane, whereas there is a shortage of suitable published papers in the public domain for Rockhampton suburban households. Although no detailed water consumption data is available for the average Rockhampton household some comparisons will be made using available data. Note: Please note the daily water use figures are based on 4.67 persons per household (due to the tenant’s third child moving into the Research House in May. The figures have been averaged for 4.67 persons over the year). Therefore, the Brisbane data has been adjusted to a 4.67 person household for the purpose of this comparison. The Brisbane water data was taken from the Brisbane City Council data, which was current at 28 December 2003 and is averaged over the 12 months prior to that date. The water used by the dishwasher (Dishlex) and front-loader clothes washer (Westinghouse) will be benchmarked against the Australian/New Zealand Standard for commonly used ‘AA’ and ‘AAA’ appliances respectively, and Brisbane Water data for appliances [11,12,13,15]. Due to variations in user patterns and the various cycles of the appliances, no comparative analysis will be made against the manufacturers’ published information for water use. Rainwater is being captured and held in two tanks of 2,000L and 5,000L capacity. Use of the tank water is restricted to gardens due to health risks associated with drinking tank water and cost impacts of other re-use options. The tenants manually operate watering from the tanks. The quantity of to wn water saved, and rainwater used, from these tanks Rainwater tank will be calculated and costed, based on tariff charges from various councils in Central and South-East Queensland, to determine values in terms of dollars saved. Ongoing analysis of rainwater captured and used will be made over a further period of time as insufficient water has been used at this stage. The project team is investigating ways of maximising the use of tank water in the future and this will be reported in future water data reports.
5.0
Water use data and findings
Total water use 1 December 2002 – 30 November 2003: 419,512L
Outdoors 51%
Laundry 6%
Kitchen, drinking and cleaning 15%
Showers and bath 18% Toilet flushing 10%
Figure 1: Research House - Total annual water use 2003 Note: The above overall water use Figure 1 for the Research House includes data for whitegoods in the kitchen and laundry segments.
Whitegoods water use 1 December 2002 – 30 November 2003: 29,302L [7%].
Other household use 93%
Washing machine 4%
Hydrotap 1.0%
Dishwasher 2%
Figure 2: Research House – Whitegoods annual water use 2003 Note: The ‘other’ segment in Figure 2 includes all other indoor water used in the Research House apart from whitegoods.
Over the year, the total average daily water consumption for the Research House was 1,150L made up of 49% for indoor use and 51% for gardens, lawns and other outdoor use (Figure 1).
The dishwasher uses approximately 29L and the clothes washer uses 43L of water per day respectively, which is approximately 7 percent of the total water usage of the Research House [12 (figure 2)]. The wet areas, such as the shower and bathrooms, used a total daily average of 211L, which equates to approximately 18% of household water consumption. Shower and bath usage has been combined in line with the Brisbane data. The toilets use an average of 116L a day, which is approximately 10 percent of total household water consumption. Of the total water consumption for the year, 14% was used in cooking, cleaning and drinking, which includes the Zip hydrotap (instant boiling and chilled filtered water dispenser). Tenants usage of the hydrotap averaged 9L a day. The hot wa ter average daily use in the Research House for the year was 129L a day or 11% of the total water use. The outdoor water usage was initially very high in the first two months (October and November 2002) due to the fitting of incorrect sprinklers, which wasted huge quantities of water through over-watering of the gardens and lawns. Installation and calibration of the correct low flow sprinkler heads provided a more efficient watering system. Even with this intervention, outside water use still accounts for a substantial proportion of the households total water use – 588L/day (51%). During the summer period (December 2002 – February 2003), the unfiltered mains inlet for town water interfered with the accuracy of the water sensors. The fine dirt particles in the town water supply slowed down the turbine motion of the transducers giving low water flow readings. As a result the reading for total outdoor water use during summer 2002-2003 is suspected to be lower than actual use. An inline fine filter was installed at the mains inlet for the house. The pattern of water usage became more consistent during the second half of the year (winter and spring seasons), giving further confidence that the transducers were giving an acceptable degree of accuracy in the readings.
6.0
Discussion
6.1
Outcome overview Table 1: Daily water use table – The Research House compared to a Brisbane city household averaged over the year [5,10,22] Daily average water consumption 2002- 2003 Area Outdoors Showers and bath Toilet flushing Laundry tub Kitchen sink and cleaning Clothes washer Dishwasher Drink dispenser Total household
Research House 588L 211L 116L 26L 128L 43L 29L 9L 1,150L
Brisbane City 668L 350L 130L 30L 140L 80L 45L 12L 1,455L
Table 1 shows the total daily water consumption for the Research House is 1,150L and the annual water consumption is 419,512 litres. An average Brisbane family uses 1,455L per day or 531,075 litres per year. The percentage of this water used indoors and outdoors is similar between the two households [5,10,22]. Even with a metered sprinkler system, moisture sensors and tank water available, the Research House still uses an average of 588L per day on the gardens. Although this is 100L per day (or 36,500 litres per year) less than the average Brisbane household, it suggests that there are further opportunities to save water by reducing water use outdoors.
Figure 3: Daily water use chart – Research House compared to Brisbane household (figures adjusted to 4.67 person household) Daily Average Water Usage
Average Daily Use (Litres)
700 600
668 588
Brisbane City 500 Research House 400 350
300 211
200 130
140 128
116
100 30 26
80
43
45
29
12
9
0 rs g h her Tub her ing hin Bat doo dry was was ean lus l s& n h Out F r c s s u t i e e D le w La th k& Toi Clo Sho Sin en h c t Ki Usage
g kin Drin
Note: Consumer patterns would influence the amount of water used or saved. Longer showers, full baths, garden sprinkling times will have dramatic impacts on water used in a household.
6.2
Outdoors
In the year, the Research House used 214,620 litres of water for outdoor use. Figure 3 shows a little over 80L of water per day have been saved outdoors. Further studies will be undertaken to look at ways of reducing this water usage. This will be documented in future water data reports.
6.3
Shower and bath
The water consumption in the shower and bath is influenced by user patterns as well as the flow control rate (9 litres per minute) of the water efficient showerheads. When compared to Brisbane household figures (figure 3 refers), the ‘wet areas’ of the Research House, such as the shower and bathrooms, are using approximately 139L or 40% less water per day. This can be attributed to the water saving devices (flow restrictors and efficient shower heads) and the highly efficient heat pump hot water system [15]. It is known that showers are the preferred option for the Research House tenants where as the preference is unknown for the Brisbane household. Water saving Table 1 shows that the tenants’ water use pattern in the Research House for the shower and bath resulted in an average water consumption of 16,490 litres per person per year. In comparison, the average water consumption in a typical Brisbane household is 27,355 litres per person per year. The approximate average yearly water saving is 10,865 litres per person.
Table 1 also shows that in the Research House, the use of an efficient showerhead with a maximum flow rate of 9 litres per minute (9L/min) has the potential to save approximately 20,000 litres of water per person per year (20,000L/pp/y). This is in comparison to a standard showerhead of 20L/min based on the same user time per person per year as in the Research House. The average shower times in the Research House are between five to eight minutes. With standard flow rates being up to 20L/minute, water efficient showerheads at 9L/minute can potentially save up to 11L/minute. With average shower times being between 5 to 8 minutes, this equates to potential water savings of between 55 to 88 litres of water per shower. Hot water The amount of hot water used depends on the duration of the shower, the flow rate of the water-saving showerhead or the quantity of water in the bath, the type of water heater installed and as does the pattern of use. Research House tenants’ household with the heat pump hot water system (Quantum) used an average of approximately 129L per day. By comparison a typical Brisbane household with a 315L off-peak electric storage system used an average of approximately 140L a day. Accordingly, Research House has achieved annual hot water saving of around 4015L or 8.0% less than the conventional electric storage system. The shower and bath area alone can realise total water (hot and cold) savings of at least 139L a day or 50,700 litres over a year [11,15]. A higher efficient (litres/kilowatt hour) hot water system, heats a larger volume of water (litres) for the equivalent units of energy consumed (kWh). The quicker recovery period and the efficient conduction of heat into the stored water for the heat pump water heater (Quantum) means the stored hot water stays at a higher temperature over a longer period, with the benefit that less hot water is used in the Research House.
6.4
Toilet flushing
The data for toilet flushing shows that 14L/day or 5,110L/year are saved at the Research House through the installation of dual flush systems, in comparison to a similar Brisbane household.
6.5
Laundry tub
The Research House laundry tub tap realises a 4L/day saving or 1460L/year whe n compared to a Brisbane household.
6.6
Kitchen sink and cleaning
The kitchen, cleaning and drinking water accounts for 12L/day saving which is an additional 4380L/year compared to a Brisbane household.
6.7
Dishwasher and clothes washer
The dishwasher and clothes washer in the Research House with their higher water conservation ratings have achieved water savings of 16L/day and 37L/day respectively. The selected dishwasher (Dishlex) (‘AAA’ water rating) and clothes washer (Westinghouse)(‘AAA’ water rating) appliances installed in the Research House are delivering water savings of at least 40% over commonly used household
appliances in Brisbane which have a ‘AA’ water conservation rating. Standard clothes washers and standard dishwashers are usually classified as AA-rated. The (‘AAA’ water rated) dishwasher in the Research House uses on average 30L per load, whilst a typical Brisbane household dishwasher (‘AA’ water rating) uses around 45L per load. As most dishwashers are used once on a daily basis this equates to an annual saving of 5,475 litres of water. The front loader clothes washer (‘AAA’ water rating) in the Research House uses an average 45L per load while a typical Brisbane household top loader clothes washer (‘AA’ water rating) uses around 80L per load [8,12]. The front loader clothes washer at the Research House has a water volume selection panel, which enables the operator to choose to use less water. Tenant feedback confirms that this option is regularly chosen. Annual water savings of 12,775L have been calculated when compared to standard ‘AA’ rated top loader clothes washers. The selection of water efficient appliances in the Research House, such as the dishwasher and clothes washer, indicates that consumers could save approximately 18,250L (18.25kL) of water per annum respectively [7].
6.8
Waste water production and reduction
Table 2 , below, shows that the total waste water discharge to the sewer in the Research House is 201,848L per year (not including water use from the hot/cold drink dispenser). Table 2 also shows that based on a standard mean maximum flow rate of 20 litres per minute (20L/min), a 55% reduction in waste water of 246,704L is achieved through the use of flow restriction devices and ‘AAA’ rated appliances in the Research House. This waste reduction has major infrastructure impacts as council has less waste water to treat and dispose of. The environment will also benefit from having less waste water being treated and released. Table 2: Total indoor waste water production for fixed maximum flow rates Outlet Kitchen sink (grey) Bathroom shower (grey) Ensuite shower (grey) Toilet (black) Ensuite toilet (black) Clothes washer (grey) Bathroom vanity (grey) Dish washer (grey) Laundry tub (grey) Ensuite vanity (grey) Bath tub (grey) Total Waste Water
Research House 9L/Min 46,720 29,795 27,043 25,780 16,563 15,695 13,012 10,584 9,490 6,269 897 201,848
Standard 20L/Min 103,822 66,211 60,096 57,289 36,807 34,878 28,916 23,520 21,089 13,931 1,993 448,552
30L/Min 155,733 99,317 90,143 85,933 55,210 52,317 43,373 35,280 31,633 20,897 2,990 672,826
Table 2 Notes: (1) Waste water at the Research House is based on actual use at a mean maximum flow rate of 9 litres per minute (9L/min). (2) Waste water reduction at a mean maximum flow rate of 20 litres per minute (20L/min) and 30L/min is a comparison to the Research House actual waste water at a mean maximum flow rate of 9L/min.
(3) Total waste water (201,848L) use does not include the hot/cold drink dispenser (3,282L). (4) Table 2 does not include outside water use.
7.0
Rockhampton city water use
Although no detailed water consumption data is available for the average Rockhampton household, the following comparison can be made from available data. The average residential water consumption in Rockhampton, for a family of 2.61 persons per household is 538,000L (538kL) per annum or 206,130L per person per annum (Widt, Aitken and Artemieff [22]), which equates to an approximate average daily use of 565L per person. The Research House consumed 420,000L per annum for a family of 4.67 persons per household or an approximate average daily use of 246L per person. Using reference data from this source, the Research House uses approximately 319L less per person per day or approximately 116,000L less water per person for the year compared to an average Rockhampton household per person. Using this as the basis of calculation, it is estimated that the Research House (4.67 persons per household) used a total of 543,752L of water less than a Rockhampton household with the same number of people (4.67).
8.0 Cost of water saving devices The installed cost of the total water saving devices in the Research House (which also provide a totally balanced, pressurised water system) is $316.00 (installed December 2002). Note: This cost is specific to the Research House and is an example only of the installed cost of the devices in a new home. Table 3 below provides a break-up of the total purchase cost only of the water saving flow restriction devices in the Research House.
Table 3: Costs of flow restriction devices Item description Qty Shower rose at 9 litres per minute (flow restriction) 2 Vanity basin at 6 litres per minute (flow restriction) 3 Kitchen sink at 12 litres per minute (flow restriction) 1 Laundry tub at 12 litres per minute (flow restriction) 1 Dishwasher/clothes washer back-flow prevention valves 2 (whisper wash) External taps back-flow prevention values 2 Total retail cost (excludes installation)
Rate ($) 23.00 19.00 26.00 20.00 27.00
Amount ($) 46.00 57.00 26.00 20.00 54.00
20.00
40.00 $243.00
Table 3 Notes: (1) Installation cost is estimated to be $73.00 in a new house at time of construction. (2) Hand held shower (Con-Serv pulsator colour chrome) with wall mount bracket and switch-cock provided in the Research House is around $210.00 recommended retail price (GST inclusive).
For more information on the pay back period of the water saving devices see Cost Benefit Analysis (section 9.0).
9.0 Cost benefit analysis Cost benefit analysis (CBA) is a technique used in the decision-making process to determine whether a cost outlay over time is a worthwhile investment. The cost (capital outlay) can be either a one-off or it may be incurred over time. The costs of the water flow restriction devices (table 3) in the Research House are a one-off cost outlay. The benefits (savings) are most often gained over time and the time it takes to recover the initial capital outlay (costs) can be assessed in the analysis by calculating a payback period. The benefits of the installed water flow restriction devices in the Research House are the cost savings made in terms of water conservation and energy conservation (hot water system). The Research House uses approximately 111,000L less water per year compared to that of a typical Brisbane household [6,8,10,15]. This means that Brisbane consumers could potentially save approximately $20.00 per annum per person on their water bill by utilising the water saving strategies adopted in the Research House. This figure has been calculated based upon Brisbane City Council two-part tariff charge of 84 cents flat rate for every kilolitre (kL) of water used plus a water access charge of $100.00 for each household. Brisbane City Council has a ‘water use cost calculator’ on their web site www.ourbrisbane.com [24] as a service to Brisbane City ratepayers, in order to calculate their mean quarterly or yearly water use cost [10,25].
By comparison, Rockhampton consumers could potentially save approximately $55.00 per annum per person on their water bill by utilising the water saving strategies adopted in the Research House. Table 3 shows the total retail cost of the water flow restriction devices is $243.00 and the estimated installation cost is around $73.00, giving a total installed cost of $316.00 for the Research House. The estimated potential savings for a Brisbane household on their water bill is $20.00 per annum per person or around $80.00 per household (4person household) per annum. The payback period calculates whether the installed costs of the water flow restriction devices are a worthwhile investment.
Table 4 below shows the calculated pay back period to recover the installed cost of the water flow restriction devices in a typical Brisbane household (based on 2003 costs). Table 4 – Payback period for water flow restriction devices (Brisbane household)
Payback period (T) Costs ($)
Savings ($)
Pay-back (years)
$316.00
$80.00
4.0
Table 4 Notes: (1) Installed cost will vary geographically within Queensland subject to transport cost and labour costs and normal market supply and demand for the devices. (2) Energy cost for water heating is not included in calculations in Table 4. However, it is estimated an additional $40.00 per Brisbane household per year is saved in reduced hot water electricity cost. The payback period (Brisbane household) will be reduced to 2.6 years when electricity water heating costs are included.
In comparison, using the formula in Table 4 for a typical Rockhampton household (4 person household), the pay back period to recover the installed cost of the water flow restriction devices is only 1.5 years. In summary, it can be concluded that the average payback period for a typical Brisbane household is approximately fo ur years, while the payback period for Central Queensland regions (Rockhampton) based on the water use in the Research House is 1.5 years. This figure has been calculated based upon the new two part user pays tariff introduced from 1 July 2004 by Fitzroy River Water, Rockhampton. The new charges are 47.5 cents per kilolitre (kL) for the first 500 kilolitre (kL) and 97 cents per kilolitre (kL) for all additional usage of water used plus a water access charge of $212.00 per annum for each household.
10.0 Conclusion Analysis of data from the Research House in comparison to the average Brisbane household confirms that significant water savings can be achieved for minimal cost outlay. Flow restriction devices to taps and showers offer real water savings for little up front cost, particularly if installed at time of construction. Dual flush (full/half flush) toilets also provide the opportunity for real water savings. Water efficient appliances – the ‘AAA’ rated clothes washer and ‘AAA’ rated dishwasher - are delivering water savings in comparison to similar but lesser rated appliances in the typical Brisbane household. The option to select the water volume in the clothes washer offers even greater water saving potential. With garden and outdoor water use being approximately 51% of the total water use at the Research House (the remaining 49% used indoors with water restriction devices) there are further opportunities to save significant volumes of water. This will be investigated and other options will be trialled to try to reduce outdoor water use without compromising the lawn or other vegetation. The use of rainwa ter tanks to collect and re-use rainwater may require further supporting technology to maximise the use of water collected. Initially minimal water re-use has been achieved with the manual drip feed supply to the gardens currently in place. This will be investigated further in future testing at the Research House. The Research House has reduced its waste water discharge by in excess of 100,000 litres per year through the use of water restriction devices and technology in conjunction with the current tenants’ usage patterns. This will be monitored in future studies and reported accordingly. Study of water use in the Research House has shown there is the potential for broad scale water savings to be achieved through households adopting ‘WaterWise’ strategies. This would mean significant benefits for Australia’s water supply and councils in treating and disposing of waste water. With increased water rates and tariffs, water saving in our homes can save consumers money and will have a positive impact on the environment. As well as water savings, proven energy savings through the use of more energy efficient products like the water heater (Quantum heat pump), dishwasher (Dishlex), clothes washer (Westinghouse) and refrigerator (Westinghouse) are deliverable outcomes. The Energy Use Study Annual Report 2002 – 2003 (by the Queensland Department of Public Works, Building Division, Built Environment Research Unit) provides more detail on the energy savings in the Research House. For more information on the Research House, visit www.smarthousing.qld.gov.au.
References Australian Greenhouse Office, Energy Efficient Appliance, [online], Available from: http://www.energyrating.gov.au/productmenu.html [3 February 2004] [16] Australian Greenhouse Office, Good Residential Design Guide Your Home –Water Use Introduction, [online], Available from: http://www.greenhouse.gov.au/yourhome/technical/fs20.htm [3 February 2004] [17] Australian Greenhouse Office, Greenhouse Gas (GHG) Emissions, [online], Available from: http://www.greenhouse.gov.au/coolcommunities/strategic/ [3 February 2004] [18] Australian Bureau of Statistics, Environment Rivers, inland waters and groundwater (water use), [online], Available from: http://www.abs.gov.au/CA25670D007E9EA1/0/AC692937B0A5A313CA2569E700146DED?Op en [3 February 2004] [20] Australian Standards, AS/NZS6400: 2003, Water Efficient Products –Ratings and Labelling, [online], Available from: http://www.standards.com.au/catalogue/script/Result.asp?PSearch=false&SearchType=simple &Db=AS&Degn=6400&Keyword=&Search=Search&Max=15 [3 February 2004] [21] Brisbane City Council, Water Conservation –Average Household Water Usage, [online], Available from: www.brisbane.qld.gov.au/BCC:STANDARD:1771298931:pc=PC_922 February 2004] [10] Brisbane City Council, Water Usage Patterns, [online], Available from: www.brisbane.qld.gov.au/BCC:STANDARD:1771298931:pc=PC_912# [May 2004] [24] Brisbane City Council, Water Cost Estimates , [online], Available from: www.brisbane.qld.gov.au/BCC:STANDARD:1771298931:pc=PC_912# [May 2004] [25] Central Queensland University, Faculty of Engineering and Physical Systems, Research House, [online], Available from: http://www.engineering.cqu.edu.au/researchhouse/ [3 February 2004] [9] Bosch Australia, Gas Hot Water, [online], Available from: http://www.bosch.com.au/content/language1/html/1708.htm [3 February 2004]. [14] CSIRO Sustainable Ecosystems, Australian Water Use Statistics Report ? on Australian Water Futures, [online], Available from: http://www.cse.csiro.au/research/Program5/publications/0103f.pdf [3 February 2004 [5] Con-Serv, Flow Restrictions Devices and Water Saving Shower Heads, [online], Available from: www.con-serv.com.au [3 February 2004]. [23] Department of Environment and Heritage, Domestic Water Consumption, [online], Available from: Department of Environment and Heritage [3 February 2004] [4]
Department of Housing, Research House, [online] Available from: http://www.housing.qld.gov.au/builders/research_house/index.htm [3 February 2004] [6]
Department of Housing, Smart Housing, [online], Available from: http://www.housing.qld.gov.au/builders/smart_housing/ [3 February 2004] [7] Department of Housing, (August 2002), Research House Flyer, [online], Available from: [4 February 2004] [26] Dr Peterson, L., E., (June 2003) Hot Water Systems Report, Queensland Department of Public Works, Building Division, p. 1-18. [11] Electrolux Australia, Whitegoods Products, [online], Available from: http://www.electrolux.com.au/node139.asp [3 February 2004] [12] Natural Resources and Mines, International Year of Fresh Water – Domestic Consumption. Quantum Energy Technologies, Energy Efficient Hot Water, [online], Available from: http://www.quantumhotwater.com/ [3 February 2004] [15] Rocky Mountain Institute, Water, [online] [1] Available from: http://www.rmi.org/sitepages/pid15.php [3 February 2004]. Rocky Mountain Institute, Commercial, Industrial and Institutional Water Efficiency, [online], Available from: http://www.rmi.org/sitepages/pid276.php [3 February 2004]. [27] Save Water, Water Conservation –Why Save Water? [online] Available from: http://www.savewater.com.au/default.asp?SectionId=5&ContentId=131&Page=2&SortTag=269 [3 February 2004] [3] Sustainable Energy Authority Victoria, (2002), Energy Smart Housing Manual, [online], Available from: http://www.seav.vic.gov.au/ftp/buildings/5starhousing/ESHousingManualCh09.pdf [4 February 2004] [19] Water Services Association of Australia, The National Water Conservation Rating and Labelling Scheme, [online], Available from: http://www.wsaa.asn.au/frames et2.html [3 February 2004] [8] Widt J., Aitken K., Artemieff. P., (October 1999), Water Utilities Queensland Report 1997/98, Department of Natural Resources, p. 1- 56. [22] Zip Industries Australia, Hydroboil, [online], Available from: http://www.zipindustries.com/?p=1730 [3 February 2004] [13]
Appendix A What is Smart Housing? Smart Housing is simple, common sense housing design. The Department of Housing's Smart Housing initiative aims to help Queenslanders to plan and build homes that are more sustainable over time. A Smart House is liveable, safe, secure, costefficient and environmentally-friendly. What is a Smart House? A Smart House is more socially, environmentally and economically sustainable. Social sustainability A Smart House has been designed with people in mind: Safety Safety is about preventing injuries in and around the home. Features such as reduced-slip flooring, a lockable cabinet for storing poisons and medicine, and ensuring that the kitchen is not also a passageway can improve safety in the home. Security Security is about using design and fixtures or fittings to reduce crime. Security screens on doors and windows, adequate lighting of all doors that open to the outside, and being able to observe the neighbourhood from inside the home will improve security. Universal design A universally designed home is flexible and comfortable for people with varying abilities and at different stages in their lives. Universal design is about your home working for you - now and in the future. This means having wide hallways and doorways, level entries to the house and main living areas, and at least one bathroom/toilet and one bedroom accessible for a person with restricted mobility.
Environmental sustainability A Smart House is resource efficient. A Smart House will reduce environmental impacts through efficient use of water and energy resources and careful selection of materials to reduce waste [6]. Water efficiency You can achieve water efficiency by choosing water saving showers and taps and consider using water tanks for watering the garden and flushing the toilet.
Water efficiency can bring other benefits besides reduced water bills. Some of these benefits are: • • • •
Energy savings – heating, pumping and treatment of water is reduced; Water service facility investment reduction; Environmental benefits – more water available for local streams, wetlands and the ecology; and Higher worker productivity – worker productivity and service quality may be higher due to a lower absenteeism [27].
Waste efficiency Careful design and planning can save materials being wasted during initial construction. It may also reduce the need for expensive modifications as the occupants’ needs change. Energy efficiency Passive solar design features such as house orientation, ventilation, insulation and adequate shading can improve energy efficiency. In many cases, it is possible to keep the interior of the home cool in summer and warm in winter without resorting to artificial heating and cooling devices. Economic sustainability A smart house is cost-efficient over time. This means smart features are included in the initial design and construction, reducing the cost of changes and modifications in the future. Altering an existing home to accommodate changing lifestyles can cost up to three times more than including the same features in the initial design and build stage. Using materials with low long-term maintenance costs will save money over the life of the house. Installing appliances with high energy-star ratings will also reduce ongoing expenses. Smart Housing may even increase the resale value of your home because it meets the needs of a wider range of people.
Appendix B
