What heat pump installation involves

Once you've decided a heat pump is right for your home, the next worry is the disruption. This guide walks through what actually happens during a heat pump installation — how long it takes, whether you need to move out, the radiator and cylinder questions, and planning permission. For a quote and a free survey, start with the calculator or call 07979529536.

How long does installation take?

Most air source heat pump installations take two to four days for a typical home. Straightforward swaps can be quicker; jobs needing several radiator changes or extra pipework take longer. Your installer gives a firm timescale after the heat-loss survey.

What happens during installation?

The installer mounts the outdoor unit on a base or wall bracket, fits or relocates the hot water cylinder, connects it to your heating circuit, upgrades any radiators that need it, runs the electrical supply, then commissions and balances the system. They'll explain the controls before leaving and handle the grant paperwork with Ofgem.

Can I stay at home?

Yes, you can normally stay at home throughout. There will be some disruption — heating and hot water will be off for parts of the work, and there's drilling and movement of installers in and out — but you don't need to move out. The installer will let you know when water and power are briefly interrupted.

Will I need new radiators?

Sometimes, but rarely all of them. Because heat pumps run cooler, some rooms need larger radiators to deliver the same warmth. The heat-loss survey identifies exactly which (if any) need upsizing. Many homes need just a few changed; some need none, especially if radiators were already generously sized or you have underfloor heating.

Do I need planning permission?

Most installations fall under permitted development and don't need planning permission. Exceptions include listed buildings, many conservation areas, and cases where the unit sits close to a boundary or faces a road. A good installer checks your local rules and handles any application. Permitted-development limits were relaxed in 2025, making more installs straightforward.

Do I need a hot water cylinder?

Almost always, yes. Heat pumps heat water to a lower temperature than combi boilers, so they store hot water in a cylinder rather than heating on demand. If you currently have a combi boiler with no cylinder, you'll need space for one — typically an airing cupboard or loft. If you already have a cylinder, it may need replacing with a heat-pump-suitable one.

How much space is required?

The outdoor unit is roughly the size of a large suitcase or air-conditioning unit and needs space around it for airflow — usually a patch of external wall, garden or flat roof with about 30cm clearance and a clear front. Inside, you need room for a hot water cylinder. Most homes, including terraces and many flats, can accommodate this.

Related guides

• What it all costs — including radiator and cylinder extras.
• Is my home suitable? — flats, solid walls, listed buildings and more.
• Heat pumps explained — how they work and how warm they keep a home.