Can air conditioning heat your home? Running costs vs gas

Every system we fit heats as well as cools. People are often surprised by this, because an air conditioner sounds like a cooling-only machine. It is not. It is a heat pump that can run in either direction, and in winter it can be a cheaper way to warm a room than you might expect.

A wall-mounted unit has two halves: the indoor unit on your wall and the outdoor unit outside. In cooling mode, it takes heat from inside your room and releases it outdoors. In heating mode, it runs the same cycle backwards: it pulls warmth out of the outside air, even on a cold day, and releases it inside through the indoor unit. No fuel is burned in your home. The electricity only drives a compressor and fans, which is why the system can produce more heat energy than the electrical energy it uses.

To compare air conditioning heating with gas fairly, you need two things for each fuel: the price per unit (kWh) and how efficiently that unit turns into heat in your room.

Electricity and gas prices. Under the Ofgem price cap (opens in a new tab) for 1 October to 31 December 2026, the Direct Debit average across England, Scotland and Wales is 26.32p per kWh for electricity (no VAT from 1 October 2026) and 7.97p per kWh for gas (including 5% VAT).

Heating efficiency. Our Bronze package, the Samsung WindFree Comfort (3.5kW size), has a seasonal heating efficiency (SCOP) of 4.6 on Samsung's UK data sheet, meaning it turns roughly 1 kWh of electricity into about 4.6 kWh of heat over a typical UK heating season.

A new gas boiler must meet a minimum efficiency of 92% under the Building Regulations' Boiler Plus standard (opens in a new tab), in force since April 2018.

Cost per kWh of heat delivered:

On these rates, the Bronze package works out cheaper per kWh of heat than a brand new gas boiler at its minimum legal efficiency, and older, less efficient boilers running below 92% would cost more again. Your actual bill also depends on how big the room is, how well insulated your home is, and how many hours a day you run the system, which is why we cannot give you a single annual figure that applies to every home. What we can promise is that the system is sized correctly for your room, which is the biggest single factor in keeping running costs down.

Manufacturers publish two heating efficiency figures. COP is measured at a single outdoor temperature in a lab, so it can look impressive without reflecting a full winter. SCOP is a seasonal average across a range of outdoor temperatures, which is closer to how the system behaves across an Essex autumn and winter. That is why we have used SCOP, not COP, for the running-cost comparison above; using COP instead would have made the air conditioning figures look even better, so SCOP is the fairer, more conservative choice.

SCOP figures for our other five packages are on each manufacturer's own data sheet, and we can go through them with you at your free survey.

• A room without gas central heating, such as a garden room, loft conversion or conservatory, where running a new gas pipe is impractical. One unit then heats and cools the space all year.
• Topping up one room rather than heating the whole house, for example an early morning warm-up in a home office before the main heating comes on.
• Homes without mains gas, where the real comparison is with electric heaters or oil, not gas, and heat pump technology wins by an even wider margin.

It makes less sense as a full replacement for a well-performing gas central heating system across a whole house, where the installation is a bigger, separate decision from a single room's air conditioning.

A correctly sized system is the single biggest factor in running cost. That is why every air conditioning installation we carry out starts with a free survey rather than a guess from a floor plan. A few habits also help on the day: closing doors to the room you are heating, using the thermostat rather than switching the unit fully on and off, and bleeding obvious draughts around windows and doors before relying on the system to make up for them.

All six packages on our price list heat and cool from the same unit, so you are not paying extra for a heating-only or cooling-only limitation. A living room air conditioning installation is one of the most common places to add this kind of heating top-up, because a living room often has the most glass and the most heat loss in the evening.

If you are planning for an open-plan or larger living space, our living room air conditioning guide covers sizing and placement in more detail, including when a 3.5kW or 5kW unit suits the room better than the standard bedroom size.