Energy Demand
The first step to consider is to improve the energy performance of the building fabric. This is expressed as the U-value of the various building elements (roof, walls, groundfloor, windows and doors). Significant reductions can be achieved by specifying appropriate roof insulation, wall insulation and energy efficient windows. Other measures that improve the energy performance of the builiding fabric are the air tightness of the building and the ventilation characteristics.
The type of fuel that will be used also has a significant impact on the carbon emissions of the building. The emission factor of the various fuel types are very different. Electricity for instance has much greater carbon emissions per unit of energy than natural gas. Clearly the use of electricity for space heating has a signicantly adverse effect on the carbon emissions of the house.
The department of communities and local government has published a document looking forward to the energy requirements of buildings in 2010 and 2013 (Building Regulations Energy efficiency requirements for new dwellings, 2007). For an example detached house it considers the following measures a minimum requirements by 2010. This would be sufficient to achieve a 25% reduction of DER over TER under part L of the 2006 building regulations.