Heating
Most people buy air conditioning to stay cool, then discover that the best thing about it is how well — and how cheaply — it heats. Every modern air conditioner is also a heat pump, and used in reverse it’s one of the most efficient ways to warm a room on demand. This guide explains how that works, why it’s so cheap compared with the heating you’re used to, and how to get the most out of your system in winter.
How a heat pump heats
It sounds almost too good to be true: your air conditioner can pull warmth out of cold outdoor air and deliver it indoors. But that’s exactly what a heat pump does. Even when it’s chilly outside, the air still contains plenty of heat energy, and the refrigeration cycle — the same one that cools your room in summer — can be run backwards to capture that heat and release it inside.
The crucial point is that the unit is moving heat, not making it. A traditional electric heater turns one unit of electricity into one unit of heat. A heat pump uses one unit of electricity to move three or four units of heat from outside to inside. That efficiency is why it’s so cheap to run, and why heat pumps are central to the UK’s plans for low-carbon heating.
What “three or four times more efficient” means in practice
This efficiency is measured as the coefficient of performance (COP), or across a season as the SCOP. A heat pump with an SCOP of 4 delivers four units of heat for every unit of electricity it draws — an effective efficiency of 400%, compared with 100% for direct electric heating. In real terms, you’re getting around £3–£4 of heat for every £1 of electricity, which comfortably beats most forms of on-demand heating.
Why instant, room-by-room heat is so useful
Central heating warms the whole house whether you’re using every room or not, and takes time to bring radiators up to temperature. An air conditioning heat pump does the opposite: it delivers warmth almost instantly, directly into the room you’re in. On a cold spring or autumn morning when the central heating hasn’t kicked in, you can warm the kitchen or living room in minutes without heating the entire house.
This zone-heating approach is both convenient and economical. You heat only the space you’re using, only when you’re using it, and you get there fast. For home offices, bedrooms used at different times, and open-plan living areas, it’s a genuinely better way to stay warm.
Does it work when it’s really cold?
A common worry is that heat pumps give up in freezing weather. Modern units are far more capable than their reputation suggests — quality systems keep delivering useful, efficient heat well below freezing, down to around -15°C or lower depending on the model. Efficiency does fall as the outside temperature drops, because there’s less heat in the air to harvest, but a correctly sized system will keep your rooms comfortable through a typical British winter. In the coldest snaps it simply works a little harder.
Occasionally in cold, damp conditions the outdoor unit will pause briefly to defrost itself — this is normal and automatic, and takes only a few minutes.
Getting the best out of it in winter
A few habits make heat-pump heating cheaper and more comfortable:
- Set a steady, sensible temperature and let the inverter hold it, rather than blasting it to maximum and switching off.
- Use scheduling so the room is warm when you arrive and not heating an empty space.
- Keep doors closed in the room you’re heating so the warmth isn’t lost to the rest of the house.
- Service it annually — clean filters and coils keep heating efficiency at its peak.
- Don’t fight your insulation. Good curtains, blinds and draught-proofing let the system do less work for the same comfort.
How it compares to your other options
Against direct electric heaters, a heat pump is three to four times cheaper for the same warmth — no contest. Against gas central heating, the picture depends on tariffs and how you use it, but for heating individual rooms on demand, rather than the whole house, a heat pump is often the more economical and far more controllable choice. And unlike a gas boiler, it does double duty as cooling in summer, so a single system covers you all year.
A system that works in every season
The beauty of air conditioning as heating is that you’re not buying a separate appliance — the cooling system you want for summer is also an efficient heater for winter, at no extra hardware cost. Many of our customers end up using their system for heating far more than for cooling, and it’s the running cost that converts them.
If you’d like to understand what a heat pump would cost to heat your rooms, we can run the figures for your home and tariff as part of a free, no-obligation quote — so you can see the winter savings for yourself.
