The Eco-Refurbishment of a 19th Century Terraced House: Energy and Cost Performance for Current and Future UK Climates

The UK government, responding to concerns over climate change impacts, has undertaken to reduce CO2 emissions to 80% of 1990 levels by 2050. This scale of reduction will require major improvements in the energy efficiency of the existing UK building stock, which is the dominant consumer of fossil fuel-generated energy. Housing is a key sector, and since 70% of all current homes in the UK will still exist in 2050 then low carbon refurbishment is critical if CO2 reduction goals are to be met. This paper uses computer modeling to examine the annual operational energy performance, long term energy cost savings and internal thermal conditions for a 19th century terraced house that was eco-refurbished to near a Passivhaus standard. The dwelling was modeled for three locations (Edinburgh, Manchester and London) using current and future climate scenarios (2020s and 2050s under high carbon emission scenarios). Simulation results suggest that there would be very little diminution in heating demand in the future for the house with no refurbishment, whilst the eco-refurbishment produced a significant reduction in energy demand and CO2 emissions. Analysis of the payback period and net present value indicate that the economic optimum varies according to energy prices and that the high construction costs incurred for an eco-refurbishment to a near Passivhaus standard could not be justified in terms of a cost/benefit analysis.