This guidance covers the issues associated with installing a heat pump in a historic building. It describes the different options available and how they work. Advice is also provided on how to minimise the potential damage to the fabric of the building in the design of the installation. Before installing a renewable energy technology in a building, all available energy efficiency measures, including low-energy lighting, heating controls and improved insulation, should ideally already have been made. This guidance note is aimed at providing advice for building owners and occupiers who are considering installing a heat pump to generate their own energy. It will also be useful for architects, surveyors, building contractors or similar building professionals who need to make the appropriate selection of equipment and method of installation to work within a historic building. This guidance note is one of a series of five guidance notes covering the installation of renewables and low carbon technologies such as photovoltaics, solar thermal, hydroelectric and wind.