At the end of this session you should be able to:
Appreciate that secondary buildings, even a ‘small’ electricity only portakabin needs to have their own sub meter so that each building’s energy load is understood and remedial action taken where necessary. Understand the type of meters available and their potential cost and benefit
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To ensure effective monitoring and control metering arrangements need to be in place for multiple buildings. Secondary or Sub Mtrs may need to be installed (read only by building occupants) Often the main building will have the billing gas and elec meters and the secondary building(s) will have little or no ‘sub’ metering.
The secondary building may be a single portakabin (elec only)
Installing sub metering can help reduce consumptions by 10%
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Lots of schools have portakabins heating space and water by electricity. Often there is little control (on/off only). These can be difficult to heat and so the tendency may be to leave the heating On. Elec costs x3 more than Gas and is almost x3 as damaging to the environment. Less effective controls may result in high consumption and cost. Sub metering should reduce consumptions and will improve the main buildings energy ratings (buildings less than 500m2 consumptions should be excluded)
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Where there are a number of buildings on site where none of the secondary buildings energy load are sub metered, then we cannot accurately assess any of the buildings energy load. The regulatory required Display Energy Certificate (DEC) energy ratings will be inaccurate and based on floor area apportionment only but will still have to be procured and displayed – since January 2013 the regulations apply to buildings larger than 500m2 so they now need their own Certificate Such buildings will have the same energy rating shown on their individual DEC so the cost of procurement although necessary is wasted. Better to install sub metering so that each of the building loads can be accurately assessed, controlled and reduced.
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Sub meters when installed will only be read by school staff and can be installed by your existing contractors (electrician for electricty sub meter and boiler maintainer should be able to install a gas sub meter or a heating sub meter) These need not be expensive £50 for an electricity sub meter but the cost of installation needs to be added - perhaps a couple of hours work -dependant upon the situation on site but do obtain a quote and for electricity sub meters do ensure that the point chosen to install the sub meter is supplying the whole or most of the building’s supply.
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Gas sub meters may look like a billing meter but perhaps without a meter serial number and in secondary buildings these can be added in their boiler houses where the gas supplies the boilers. If a secondary building does not have its own boilers it either ‘imports’ the heat via hot water pipes which originate from the main building’s boiler house Or it has its own heat emitters usually electricity in which case the electricity sub meter when/if installed will pick up this load.
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Where hot water pipes bring in heat to a building which then typically feeds radiators the heat can be measured via a heat meter and your existing boiler maintainer ought to be able to give a quote for such an installation. The readings ought to be in kWh. Gas and Heating sub meters may cost £300 each plus installation.
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Some Secondary buildings may already have sub metering installed either electric or gas/heat sub meters but site staff may not be aware of their existence. Building regulations (Part L) demand the installation of such so recently undertaken works (new build/refurbishment) should have provided sub metering.
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You should now:
appreciate that secondary buildings, even just a ‘small’ electric only portakabin need to have their own sub meters so that each building’s energy load is understood and remedial action taken where necessary. Understand the type of meters available and their potential cost and benefit