How heat pumps work — and the myths, honestly answered
A heat pump doesn't burn fuel to make heat — it moves heat. It works like a fridge in reverse: it extracts warmth from the outside air (or the ground) and concentrates it to heat your home and hot water. Because it moves heat rather than creating it, a good system delivers several units of heat for every unit of electricity it uses — which is why it can be efficient even on a cold day.
Below are the questions people ask most, answered straight — no sales pitch.
Common myths, honest answers
Myth: "Heat pumps don't work in cold weather."
Honest answer: Modern air source heat pumps work effectively down to around -15°C — colder than almost anywhere in the UK gets. Norway, Finland and Sweden, all far colder than us, have the highest heat pump adoption in Europe. They work fine here.
Myth: "You need underfloor heating."
Honest answer: You don't. Heat pumps work with normal radiators. Because they run at a lower water temperature than a gas boiler, a few radiators may need to be slightly larger — but most modern radiators are already big enough. A good installer will tell you exactly which, if any, need upgrading.
Myth: "They're really loud."
Honest answer: Modern units run at roughly 40–50 decibels measured a metre away — quieter than a dishwasher, a touch louder than a fridge. Planning rules also set minimum noise-distance requirements to keep neighbours happy.
Myth: "You always need planning permission."
Honest answer: Most installations are covered by Permitted Development rights, so no planning application is needed. The usual exceptions are listed buildings, conservation areas and some flats. Your installer will confirm what your specific property needs.
Myth: "They take ages to heat the house up."
Honest answer: Heat pumps are designed to run steadily and keep the home at a constant temperature, rather than blasting heat in short bursts like a boiler. Once you get used to the "always-on, low-output" approach, the house tends to feel more comfortable overall — and it's part of why running costs stay competitive.
Myth: "The grant is hard to apply for."
Honest answer: You don't apply at all. Your MCS-certified installer applies on your behalf and the grant is deducted from your invoice before you pay. It's one of the simplest government grants to access. Here's how it works.
Air source, ground source, air-to-air — what's the difference?
- Air source (air-to-water): the most common choice. Takes heat from the outside air and feeds your radiators and hot water. Grant: £7,500.
- Ground source: takes heat from the ground via buried pipes. More efficient, but a bigger install and higher upfront cost. Grant: £7,500.
- Air-to-air: heats (and cools) your rooms with warm air, but does not provide hot water. Newly eligible in 2026. Grant: £2,500.
See the full grant table and the £9,000 off-gas oil/LPG uplift on how the scheme works.
Wondering if your home suits a heat pump?
The honest answer depends on your specific property. Our free 2-minute check is the quickest way to find out — and we'll connect you with a vetted MCS-certified installer if you'd like a proper survey.
Check my eligibility →Keep reading
How the Boiler Upgrade Scheme works
What you can get and how the grant is claimed for you.
Who qualifies for the grant?
The three tests, the scrapped EPC rule, and the £9,000 off-gas uplift.
What a heat pump really costs
Illustrative 2026 price ranges and what you might pay after the grant.
Sources: general heat pump performance and installation guidance per the Energy Saving Trust; grant amounts and technology eligibility per Ofgem — Boiler Upgrade Scheme. Guidance is general and accurate as of July 2026 but may change — always confirm specifics with an MCS-certified installer. UK Heat Pump Grant is a service of GrafterUK Ltd (Co. No. 17303977) and is not affiliated with the UK Government; this page is guidance only.