Heat pump basics

A heat pump heats your home and hot water by moving heat from the outside air (or the ground) into your home. It's an electric alternative to a gas or oil boiler. This guide covers what you need to know before you get a quote.

We're not yet introducing heat pump specialists. You can register your interest and we'll let you know when we are.

How it works

An air source heat pump is a unit outside your home that works like a fridge in reverse. It takes heat from the outside air, even on cold days, and raises it to a temperature that can heat radiators or underfloor heating and a hot water cylinder.

Heat pumps are efficient because they move heat rather than create it. For each unit of electricity used, a well-designed system typically delivers several units of heat. How efficient yours is depends heavily on the design and installation.

Things that make a difference

Lower flow temperatures. Heat pumps are most efficient when the water in your radiators is warm rather than very hot. That means radiators run for longer at a lower temperature, and some may need to be larger.

Insulation. The better insulated your home, the smaller and more efficient the system can be. Loft and wall insulation are often worth doing first.

A heat loss survey. A proper installation starts with a room-by-room calculation of how much heat your home needs. Be wary of a quote that isn't based on one.

A hot water cylinder. Heat pumps don't heat water on demand like a combi boiler, so you'll usually need a cylinder and space for it.

Siting and noise. The outdoor unit makes some noise, a little like a fan. Where it goes matters, both for your neighbours and for planning rules.

The Boiler Upgrade Scheme

The Boiler Upgrade Scheme is a government grant in England and Wales towards replacing a fossil fuel heating system with a heat pump. At the time of writing it offers £7,500 towards an air source heat pump. Your installer applies for it and takes it off the price you pay.

Conditions apply. For example, the property and the existing heating system must meet the scheme's rules, and the installer must be MCS certified. Check the current amounts and eligibility on GOV.UK before you rely on it, as schemes change.

Permissions

Air source heat pumps on houses are often allowed without planning permission, subject to conditions about size, position and noise. Listed buildings, conservation areas and flats can be different. Your installer should check.

Questions to ask

1. Will you do a room-by-room heat loss survey before quoting?
2. What flow temperature will the system run at, and which radiators need changing?
3. Where will the outdoor unit and cylinder go?
4. Are you MCS certified, and will you apply for the Boiler Upgrade Scheme on my behalf?
5. What running costs do you expect on my current tariff, and how did you work them out?
6. What do the equipment and workmanship guarantees cover?