Each answer links back to the page that covers it in depth. If your question is not here, the form at the foot of the page comes to the publisher of this guide, and we answer by email.
Cost
What does it cost to have an air source heat pump installed?
The official median for grant-funded installations in England and Wales in July to September 2026 was £12,826, with half of all jobs between £10,717 and £15,461 (DESNZ). These prices include VAT and the grant value; after the £7,500 grant most homes can get, the median job leaves about £5,326.
Why does the size of the heat pump change the price so much?
A bigger unit costs more and usually comes with more radiator and cylinder work. Across April 2025 to March 2026 the median rose from £12,164 for 6 to 8 kW to £15,366 for 12 to 14 kW. The size itself should come from your heat-loss survey.
What does a ground source installation cost?
The median for April 2025 to March 2026 was £26,500 across 365 grant-funded installations. Quarterly figures swing because the sample is small; July to September 2026 came out at £34,630.
Is there VAT on a heat pump installation?
Installing a heat pump in a home is zero-rated until 31 March 2027 and charged at 5% from 1 April 2027 (HMRC Notice 708/6). A heat pump bought without installation is standard-rated.
Timing and the grant
How long does an installation take from quote to switch-on?
The grant sets the frame: you confirm within 14 days of Ofgem's email, and once the voucher is issued the installer has 3 months to install, commission and claim it for air source, 6 for ground source. There is no official figure for days on site, so ask for a written schedule.
Who applies for the grant?
The MCS certified installer applies on Ofgem's system. Ofgem then emails the property owner to confirm the installer is acting for them, and the grant is deducted from the price on the quote.
Can the heat pump be fitted before the grant is approved?
Yes, but a retrospective application must be properly made within 120 days of commissioning, and if it is refused you pay in full. Most people wait for the voucher.
Is the higher £9,000 grant for everyone off the gas grid?
No. £9,000 is only for homes with no mains gas connection (a capped meter counts as connected) that are replacing oil or LPG heating, for applications properly made between 21 July 2026 to 31 March 2027. Off-gas homes on electric heating get £7,500.
The work itself
What is a heat-loss survey?
A room-by-room calculation of how much heat the home loses on a cold day. It sets the size of the heat pump and shows which radiators are big enough at the design flow temperature. MCS certified installers design to MIS 3005-D, the heat pump design standard.
Will my radiators need replacing?
Some may. A heat pump sends cooler water round the system, so a radiator that was just big enough with a gas boiler may fall short. The radiator schedule in the design should show each room and what changes.
Do I need a hot water cylinder?
Yes, if you have a combi boiler now. A heat pump heats a stored cylinder rather than water on demand. The design should say what size and where it goes.
Does the electricity network need to know?
Yes. The installer either connects and notifies the network operator within 28 days, where the home's new maximum demand is 60A or less and other conditions are met, or applies first where it is 60A to 100A.
Planning and siting
Do I need planning permission for an air source heat pump?
Often not in England. Under Class G the outdoor unit must be no bigger than 1.5 m³ (0.6 m³ on a block of flats), one unit (two on a detached house), pass MCS 020 a), and not be on a pitched roof or a listed building. Conservation areas add limits on walls facing a road.
Is a heat pump too noisy for a terraced house?
Under permitted development it has to pass the MCS 020 a) sound calculation, which takes the distance to neighbouring windows into account. On a terrace the position matters a lot; ask for the calculation for the spot on your quote.
After the job
What should I be given at handover?
The MCS certificate, the commissioning record, the heat-loss and design figures, building regulations paperwork, warranties, instructions for the controls and an itemised invoice showing the grant deducted.
Who do I complain to if the installation is not right?
The installer first, in writing. Then the consumer code they belong to: Ofgem lists HIES, RECC and MCS for the scheme, and each has a complaints process.
Where to read more
Costs and your own dates: the installation cost planner. The stages: how a heat pump is installed. Planning: planning permission. The paperwork: commissioning and handover. The scheme's own rules are on GOV.UK.