The impact of fabric construction methods on energy performance and costs in English dwellings

This paper investigates the impact of six different fabric construction methods (three Standard methods; three Alternative methods) on energy performance and costs, for a typical English four bedroom detached dwelling. The energy performance of the dwelling was assessed using the UK Government’s Standard Assessment Procedure (SAP), which is based on the Building Research Establishment Domestic Energy Model. The capital costs were estimated from data published by the Building Cost Information Services applied to Leicester UK area in 2011. Standard construction methods were considered to be masonry cavity walls, solid concrete floors and cold pitched timber roofs. Alternative construction methods were considered to be structural insulated panels, insulated concrete formwork and thin joint block work. Through alterations to the dwelling fabric alone, a reduction of 30% in carbon emissions of the base property could be achieved. Standard methods proved to be as effective as Alternative methods at reducing carbon emissions for an average capital cost increase of 9.1% against the base property. This was equivalent to an extra cost of £13.7 for each kg of CO2 emissions reduction. The optimum construction method that would help achieve the UK government target in terms of future zero carbon dwellings, was also discussed.