Low carbon heating, Retrofit technical considerations

Air Source Heat Pumps

Introduction

An air source heat pump (ASHP) is a low carbon heating technology. ASHPs run similarly to a fridge but in reverse. The heat pump takes in outside air to warm a refrigerant, which is placed under high pressure to increase the temperature. This heat is then transferred to water which can be distributed around the house similarly to a boiler-fired central heating system. This means that ASHPs can be used to heat both radiators and hot water.

Published: 5 December 2025

This quick guide aims to introduce air source heat pumps and address some common misconceptions about their use in domestic retrofit. The document has been designed to help housing providers and local authorities advise residents about air source heat pumps and best practices.

Download the PDF below to access this Quick Guide. 

Readers that would like this document in a more accessible format should contact rise@turntown.co.uk.