This is the question we get asked more than any other, usually phrased as “they are fine in Norway, but will it actually heat my house in February?” It is a fair question and it deserves a proper answer rather than a brochure line. The short version is that heat pumps work perfectly well in a British winter. The longer version explains why they sometimes do not, which is the part worth reading.
In this guide
The short answer
Yes. An air source heat pump will heat a home through a British winter, including the cold snaps.
The physics is not really in dispute. A heat pump does not need warm air, it needs air with some heat in it, and outside air has heat in it well below freezing. It works the way your fridge works, just pointed the other way, and your fridge is perfectly happy making its inside colder than its outside. The countries with the highest heat pump uptake in the world are not warm ones. They are cold ones.
Where the doubt comes from
The scepticism did not appear from nowhere. Some of it is old news travelling well: early installations in this country, fitted before the industry knew what it was doing, produced some genuinely unhappy customers, and those stories still circulate long after the installations behind them went out of date.
And some of it is honest confusion between two different things. A heat pump becoming less efficient as it gets colder is real and expected. A heat pump failing to heat a house is something else entirely, and it is usually a sizing or installation problem wearing a weather costume.
What happens as it gets colder
Here is the honest engineering. As the outside air gets colder, two things happen at once. Your house wants more heat, because the gap between inside and outside is bigger. And the heat pump has to work harder for each unit it delivers, because there is less heat in the air to grab. Demand rises exactly as supply gets more expensive. That is the least convenient arrangement possible, and there is no point pretending otherwise.
What matters is what “less efficient” means. It does not mean the heat pump stops delivering. It means the ratio narrows. Even on a genuinely cold day, a properly specified air source heat pump still delivers more heat than the electricity it consumes, which is something no gas boiler and no electric heater can ever do. A fan heater gives you one unit of heat per unit of electricity on its best day, forever. A heat pump beats that even when it is having a bad day.
What about defrosting?
In damp, near freezing weather, frost can form on the outdoor unit. That is normal. The unit runs a brief defrost cycle, clears it, and carries on. It is designed behaviour, not a fault, in the same way your fridge freezer defrosting itself is not a fault.
The real reason a house ends up cold
- It was sized by guesswork. Somebody looked at the old boiler, or counted the bedrooms, and picked a heat pump. That is not a design. An undersized heat pump cannot heat the house on the coldest days, which is exactly when you notice.
- The emitters were never looked at. Heat pumps run at lower flow temperatures than boilers. If the radiators were sized for a boiler and nobody checked, some rooms underperform, and it looks like the heat pump is at fault.
- The building was never addressed. If heat is pouring out of a cold loft and single glazed windows, no heating system fixes that. A boiler papers over it by brute force. A heat pump is more honest about it.
All three are decided before anyone picks up a tool. This is why we go on about the heat loss survey. It is not paperwork and it is not a formality. It is a room by room calculation of how much heat your specific house loses, and it is what decides whether you end up happy. A heat pump is less forgiving of a bad design than a gas boiler is, which is why the installer matters more than the badge on the box.
Flow temperature is the thing to understand
This is the concept that makes everything else make sense, and almost nobody explains it. A gas boiler heats water very hot and sends it round your radiators. They get too hot to touch, blast heat into the room, and then the boiler switches off and the room drifts back down. That cycle is what British homes have been used to for decades.
A heat pump works best heating water to a lower temperature and keeping it moving. Your radiators end up warm rather than hot. That feels wrong the first time you touch one, and it is the most common thing new owners report as a worry.
But a radiator that is warm all day puts plenty of heat into a room. It just does it steadily instead of in bursts. And the lower the flow temperature, the more efficient the heat pump, which is where your running costs come from. It is also exactly why radiators sometimes need upsizing: more surface area at a lower temperature delivers the same heat. Our guide on whether you need new radiators goes into that properly.
You use it differently to a boiler
- Do not switch it on and off. The boiler habit of two hours in the morning and four at night works against a heat pump. It is happiest running gently for long stretches, holding the house steady.
- Do not expect a blast of heat. You are aiming for a house that is never cold, rather than one you rescue twice a day.
- Set it and leave it alone. Constantly nudging the thermostat makes it work hard for no benefit.
- Let the weather compensation do its job. A properly set up system adjusts itself as it gets colder outside. That is the point of it.
When we would tell you not to bother
If your home is genuinely poorly insulated and you have no appetite for changing that, we would rather you did not spend the money yet. A heat pump will still work, but you will pay to heat a building that cannot hold heat. Sort the loft first. That is cheaper and it makes everything after it better.
If you have nowhere sensible outside for a unit with air able to move around it, or nowhere indoors for a hot water cylinder, that is a real constraint rather than something to design around with optimism. Plenty of small terraces around Middlesbrough and Thornaby fall here, and that is a fact about the building rather than a failure.
And if you have a modern, healthy gas boiler and your actual complaint is that one bedroom is unbearable in July, a heat pump is not the answer to your problem. Air conditioning is. We would say so before you spent anything.
Teesside winters specifically
Nothing about a Teesside winter troubles a heat pump. It is cold, it is damp, and there is wind off the North Sea, and none of that is outside what these systems are designed for.
The local factors that genuinely matter are about buildings rather than weather. Newer estate homes around Ingleby Barwick, Yarm and Eaglescliffe tend to be well insulated with sensible outside space, and are usually straightforward. Rural properties towards Guisborough and past Saltburn are frequently on oil or LPG, which is where a heat pump makes the biggest difference to what you spend. Older solid wall terraces around Middlesbrough, Thornaby and Norton need the most honest conversation, because the fabric of the building decides more than anything we bolt to it.
Coastal homes at Redcar, Marske and Saltburn have one extra consideration. Salt air is hard on any outdoor unit, so siting and regular servicing matter more there than inland. That is not a reason to avoid a heat pump. It is a reason to look after it.
Finding out about your home
We are based on North Ormsby Road in Middlesbrough and cover roughly twenty miles of Teesside, taking in Stockton on Tees, Thornaby, Billingham, Norton, Yarm, Eaglescliffe, Ingleby Barwick, Redcar, Marske, Saltburn, Guisborough, Marton, Hartlepool, Peterlee and Darlington.
The survey is free and there is no obligation. Ring us on 01642 680 873. If your home is not ready for a heat pump, we will tell you what would need to change and let you decide, which is a better outcome for both of us than a cold house with our name on it.
