Heat pump myths, checked

"They don't work in cold weather"

Not true. Heat pumps are designed to operate in temperatures down to around -20°C. The average UK winter temperature is roughly 4°C per Met Office data, so British winters sit comfortably within operating range. Even below freezing there's still usable heat energy in the outside air.

Where the concern has some substance: efficiency does fall as temperatures drop, so your running costs genuinely will be higher on the coldest days of the year. The system keeps heating your home, but it works harder to do it.

"The radiators only feel lukewarm — it must be broken"

That's correct behaviour, not a fault. A heat pump runs at roughly 35-45°C versus a boiler's 60-70°C. Radiators should feel warm, not too hot to touch. That lower temperature is precisely what makes the system efficient.

The room still reaches the temperature you set — it gets there by running steadily over longer periods rather than in short, very hot bursts. Think cruise control versus constant accelerating and braking.

"You have to leave it on all the time, which must cost a fortune"

Partly a myth, partly a real change in habits. Heat pumps are designed to run continuously at low output rather than being switched on and off in bursts — and continuous running at a low flow temperature genuinely is more efficient than repeatedly heating a cold house back up.

It does mean unlearning boiler habits. Cranking the thermostat up to "heat the house faster" works against a heat pump, and tends to raise costs rather than lower them.

"They only suit new builds or very well-insulated homes"

Not true — plenty of existing and older UK properties run heat pumps successfully. Insulation and correct system design matter far more than the age of the building.

Where it's fair: a draughty, poorly insulated home will have higher running costs and may need more radiator work. Insulation improvements usually pay back better than almost any other spend, and can reduce or remove the need for radiator upgrades entirely.

"They're noisy"

Mostly outdated. Modern units run at around 40-60 dB — comparable to a fridge or quiet conversation — and most owners stop noticing within weeks. Noise matters more for planning compliance and neighbour relations than for comfort indoors.

Full detail, including the planning rules and what to do if a siting fails the noise calculation, is in our noise and planning guide.

"It'll take up loads of space"

Partly true, and worth planning for. The outdoor unit needs around a metre of clearance for airflow. Indoors, the bigger consideration is that heat pumps generally don't do hot water on demand the way a combi does — you'll need a hot water cylinder, which typically fits in a cupboard around 80cm × 80cm.

If you're currently on a combi with no airing cupboard, this is a genuine practical change rather than a myth, and worth raising early when getting quotes.

"They break down constantly and are expensive to maintain"

Not borne out. Maintenance is broadly comparable to a gas boiler — an annual service runs roughly £100-£200 (against £80-£120 for a boiler), covering refrigerant checks, filter cleaning, electrical inspection and performance verification.

A well-maintained heat pump typically lasts 20-25 years, against 12-15 for a gas boiler.

Simple things that keep one running well

• Keep the outdoor unit clear of leaves, debris and vegetation — maintain about a metre of clearance
• Check the condensate drain isn't blocked or frozen in winter
• Watch your electricity usage — if bills climb without colder weather, something's worth investigating
• Don't fiddle with flow temperature or weather compensation settings unless you understand them — these are set deliberately by your installer, and changing them is a common cause of self-inflicted efficiency problems

"The steam coming off it means something's wrong"

Normal. In cold weather the unit runs a defrost cycle to melt ice off the heat exchanger, typically lasting 5-10 minutes and often producing visible steam. It's designed behaviour.

Where sceptics genuinely have a point

In the interest of an honest picture rather than a sales pitch:

• Running costs aren't automatically lower. On a standard electricity tariff versus mains gas, costs are often close. The clear savings come on a dedicated heat pump tariff, or when switching from oil, LPG or direct electric — see our costs and savings guide.
• Installation quality varies enormously. Most reported heat pump problems trace back to poor installation — wrong sizing, wrong flow temperature, or a skipped heat loss calculation — rather than the technology itself.
• There are upfront costs the grant doesn't cover, radiator upgrades and cylinder installation among them.