Residential retrofit in the UK: The optimum retrofit measures necessary for effective heat pump use

Abstract

The Department for Business, Energy & Industrial Strategy and the Committee on Climate Change place high dependency on the electrification of heat and use of heat pump systems to achieve net zero emissions by 2050. Energy efficient buildings are essential for effective heat pump operation. However, the UK’s housing stock is amongst the least energy efficient in Europe. Household electricity demand will increase with heat pump use, meaning reinforcement to infrastructure and generation capacity. This study uses dynamic simulation modelling to determine the optimum energy efficient retrofit required to minimise energy use and electrical demand for an average semi-detached dwelling using a heat pump. Solid wall insulation is found to be critical in energy abatement, although the heat pump operates at a high demand compared with low voltage network design. A whole house retrofit in-line with current Building Regulations reduces the heating demand and emissions by 65%, and lowers the input electrical demand for the heat pump to under 1 kW. Solid wall insulation and low U-value glazing are the cost-optimal solution, achieving similar abatement. Measures that exceed building regulations are shown to lower heat demand and carbon emissions by almost 80%, highlighting scope for improvement in retrofit standards. Practical application: At present, UK policy makers have a preferred alternative to high carbon fossil fuels that is a system heavily reliant on heat pumps powered by low carbon electricity. Heat pump systems require energy efficient buildings to operate effectively. A key factor when improving building efficiency is fabric standards, which can dramatically impact the heat transfer coefficient. Retrofit of energy efficiency measures is key to future net zero success and will have large implications to consumers and supply chains alike.