Heat pumps in historic buildings : the viability of ground source heat pumps in historic buildings

This project was commissioned by Historic England and carried out by Max Fordham LLP. The research aligns directly with Historic England’s climate change and sustainability objectives. Electrifying heat is key to reducing reliance on fossil fuels across the heritage sector. No technology is better placed to electrify heat for space heating than heat pumps. The technology is mature, and if the whole heating system is well designed it will deliver comparable running costs to a natural gas system. Ground source heat pump (GSHP) technology can be deployed discretely without altering a site’s appearance, and it delivers excellent efficiency. It is, therefore, a key technology in the decarbonisation of space heating in historic buildings. The five case study visits took place between February and April 2023. Engineers from Max Fordham LLP carried out visual inspections of the GSHP installations and associated heating systems. They also interviewed building users to gauge their opinions on running costs, thermal comfort, noise and visual appearance. The engineers took as many quantitative measurements as possible, but time constraints and minimising the intrusiveness of site visits meant that most of the findings were qualitative. Assessing running costs was particularly difficult. Where data were available, they came in the form of energy bills. This made it challenging to make quantitative comparisons before and after installing the GSHPs. The users’ perceptions of running costs are reported, but the information is highly subjective according to each individual’s expectations.