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Meeting higher sustainability standards, such as Code for Sustainable Homes Level 4, does not necessarily mean lower energy costs to residents. The strategy adopted to achieve these higher standards can have a significant impact. It is possible for energy running costs to be increased if inappropriate strategies are adopted.

We have examined the estimated energy costs for different energy strategies that meet the energy requirements of Code for Sustainable Homes Level 4, which requires a 25% reduction in Regulated CO2 emissions over Part L of Building Regulations (2010).

The test dwelling was a 3-Bed 90m2 semi-detached house. Energy demands have been derived from SAP calculations, with energy costs for gas and electricity derived from Standard nPower tariffs. District heating charges are derived from our own project experience.

Our results show that:

  • Achieving Code Level 4 through energy efficiency alone facilitates a saving of only £55/yr. Assuming extra-over build costs of £4,000 to build to this standard, there is a simple payback of 80 years (benefit received by the householder not the developer).
  • For other energy strategies, the predicted annual energy cost at Code Level 4 can be more than at the baseline of Building Regulations (2010).
  • Electric strategies are more expensive to residents than gas strategies.
  • Using Air Source Heat Pumps (ASHPs) is predicted to be slightly (£57/yr) more expensive for residents in a Code Level 4 dwelling over the lower baseline standard. However, where the ASHPs do not perform to the theoretical standard, annual energy costs can become substantially more (£574/yr).
  • Energy costs for district heating can vary substantially depending on the operational model selected (low where operated on a not-for-profit basis to high where under an ESCO contract).
  • The lowest cost Code Level 4 energy strategy is the use of PV panels. However, this relies on receiving the Feed-in-Tariff for generating renewable energy. On blocks of flats where the generated electricity goes to the common parts, this may not be the case (£198/yr higher than when receiving the Feed-in-Tariff).

Energy Costs by Strategy to Code 4

Posted on September 27th, 2012