The energy rating perspective: ideal scenarios for the use of heat pumps in new build dwellings
In all cases, Elmhurst Consultancy Services has undertaken specific energy rating calculations to demonstrate that a heat pump installation can meet the Building Regulations, the Code for Sustainable Homes (CSH) and the 10% renewable energy demand in planning conditions.
Traditionally, the majority of housing built in the UK is heated by mains gas which has a good balance between energy efficiency, affordability and compliance with the Building Regulations. But what if mains gas is not available? The next most popular choice would usually be a boiler that would burn dirtier and more expensive fuels such as oil and LPG. Alternatives could include electric boilers and storage heaters - high running costs and associated carbon emissions.
These all struggle to meet the dwelling emission rate standard as defined in Part L. Additional provisions such as increased insulation, solar hot water and increased air tightness may be required just to achieve the minimum standard. The 25% improvement in energy rating required by CSH level 3 would be unthinkable without extremely costly renewable solutions.
Alternatively, modern heat pumps give flexibility in design, due to their excellent efficiency, which generally easily exceeds 200%. Using Elmhurst's latest version of SAP 2005 software to calculate the DER, shows a heat pump is an ideal choice in a dwelling where high energy standards are required. Volume developers are currently selecting air source heat pumps connected to radiators. Ground source heat pumps with under-floor heating are becoming more common in rural locations and in exclusive developments.
The revised edition of Part L, expected to be released in 2010, is expected to contain a mandatory improvement of 25% over the current energy standards. This makes it highly likely that more heat pumps will be specified. It is also likely that natural gas boilers, without any additional renewable technology, will not meet the 2010 Building Regulations. Most heat pumps should be close to meeting these new standards as part of a fully compliant building specification. Should higher energy ratings be sought (such as CSH level 4), heat pumps with the aid of other technologies such as solar hot water, will enable even this standard to be reached.
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