Air source heat pump installation: what to expect

From the first survey to handover, here's how an air source heat pump is fitted, how long it takes and what the installation costs.

Air source heat pump installation usually takes 2 to 4 days once the survey and design are done. Fitting an air source heat pump is more involved than a boiler swap, because the system is designed around your home's heat loss, but a good installer keeps the disruption low and handles the £7,500 grant for you.

Before installation: the survey

Every MCS installation starts with a survey. The installer measures each room, notes windows, walls and insulation, and calculates how much heat each room loses on a cold day. From that they size the heat pump and check whether each radiator is big enough at a heat pump's lower flow temperature.

  • Siting the outdoor unit: airflow, distance to the house, drainage and the MCS noise check.
  • Cylinder location: where the hot water cylinder will go, especially if you have a combi boiler.
  • Electrics: your supply and consumer unit are checked, and your network operator notified if required.
  • Permissions: permitted development, listed building or conservation area rules.

Installation day by day

  1. Day 1: outdoor unit and pipework. The heat pump is placed on a pad or wall bracket and pipes are run into the house.
  2. Day 2: indoor work. The old boiler is removed, the cylinder and any buffer tank are fitted and the system is connected.
  3. Day 3: radiators and controls. Any radiators identified in the survey are upgraded, and the thermostat or app is installed.
  4. Final day: commissioning. The system is flushed, filled, tested and set up with weather compensation.
Engineer fitting an air source heat pump outdoor unit

Air source heat pump installation cost

A full installation, including the heat pump, cylinder, controls, labour and commissioning, typically costs £8,000 to £16,000 before the grant. With the £7,500 Boiler Upgrade Scheme grant deducted, most homes pay between £1,500 and £8,000. See our full cost guide for prices by house size.

After installation

  • Handover: your installer shows you how to use the controls and explains how heat pumps run best (steady, lower temperatures).
  • MCS certificate: proof the system meets the standard, needed for the grant and useful when you sell.
  • Warranty registration with the manufacturer.
  • Annual service to keep it efficient and the warranty valid.

Choosing an air source heat pump installer

Choose an MCS-certified installer who belongs to a consumer code (RECC or HIES), carries out a room-by-room heat loss calculation and gives you a fixed written quote showing the expected SCOP. Every installer we work with meets those standards. Find heat pump installers near you.

Sources

Grant amounts, VAT rules and eligibility are set by government and the scheme administrators. We check them against these primary sources:

New to the jargon? See the heat pump glossary, or browse the heat pump FAQs.

Questions

The things people ask us first

If yours isn't here, ask on the form and an adviser will answer it on the call.

How long does installation take?
Most homes are fitted in 2 to 4 days. That includes mounting the outdoor unit, fitting a hot water cylinder, connecting pipework and upgrading any radiators that are too small. You'll have hot water and heating back at the end of each working day wherever possible.
How much does air source heat pump installation cost?
Supply and installation typically costs £8,000 to £16,000 before the grant, depending on the size of the heat pump and how much of your heating system needs changing. The £7,500 Boiler Upgrade Scheme grant is deducted from that, so most homes pay £1,500 to £8,000.
Will I be without heating during installation?
Usually only for a day or two while the old boiler is removed and the new system is connected. Installers plan the work so you have hot water and heating back at the end of most days.
Do I need planning permission for an air source heat pump?
Usually not. In England and Wales most air source heat pumps are permitted development, provided the unit meets size, siting and MCS noise rules. Listed buildings, flats and some conservation areas may need consent, and your installer will check this during the survey.
Will I need new radiators?
Not always. Heat pumps run at lower flow temperatures than boilers, so some radiators may need to be upsized to keep each room warm. Your installer works this out with a room-by-room heat loss calculation and includes any changes in your quote.
Who can install an air source heat pump?
To claim the £7,500 grant, it must be installed by an MCS-certified installer. They will also register the system with MCS and notify your network operator where needed.
Get started

Your warmer home starts here

Answer six quick questions to check your eligibility for the £7,500 Boiler Upgrade Scheme grant and get a free quote from an MCS-certified installer.

Check my eligibility
GetASHPCheck my £7,500 grant