Is this the end of the air source heat pump loophole?
Posted by Alistair Pilcher on 7 April 2014 at 9:15 am
Meeting the new energy efficiency and CO2 emissions targets for the construction of new buildings will become tougher when the latest revision to the Building Regulations soon comes into force. This should close a loophole where builders could adopt a limiting (worst case) thermal fabric approach, then offset that by installing an air source heat pump. The low emissions from the heat pump would compensate for the poorer performing fabric and allowed for fairly straightforward energy efficiency compliance.
Part L of the new Regulations deals with the conservation of fuel and power. It includes a new fabric efficiency target for dwellings, so offsetting a poorer quality building fabric with an air source heat pump to ensure compliance could no longer be achievable.
On 6 April 2014, Part L1A of the Building Regulations 2013 will be implemented – this document sets the standards required for new dwellings and will affect Building Regulations applications for all new homes. Compared to the current 2010 Regulations, there will be a 6% reduction in emissions rates, requiring an improved building specification in order to comply.
In the 2013 Regulations, there is the introduction of a target fabric efficiency rate. Fabric efficiency is a combination of heat loss through the fabric, thermal bridging and air tightness and also takes account of thermal mass and solar gains. It is already used in Code for Sustainable Homes assessments. Any new dwelling must meet the target for both emissions and fabric efficiency, ensuring one cannot counteract poor performance of the other.
For the fabric, u-values of the walls, floor and roof will need to be improved (lowered) by using more or better performing insulation. Reducing thermal bridging will be a must; this ensures heat losses, where there are junctions in the external elements, are kept to a minimum. Air tightness testing standards will remain the same but opting not to test a building and settling for default, punitive figure will make it more difficult to comply with the target fabric efficiency rate.
Under the 2013 Building Regulations, air source heat pumps will still be a good choice for heating new dwellings, especially when considering grants that may be available; however the specification of the building fabric will need to be better than in previous years. For more detailed information regarding changes to Building Regulations, please click here.
Photo courtesy of Alistair Pilcher
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About the author: Alistair is co-founder of Up Energy
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