How much does air conditioning cost to run in the UK?
There’s no single honest figure: it depends on your room, how long you run the unit and what you pay for electricity. As a guide, at the October–December 2026 price cap rate of 26.32p per kWh, each kWh of heat from our systems costs roughly 5p to 6.6p, against 26.3p from a plug-in heater.
Below, we show exactly how that’s worked out, with a heating and a cooling example. Every assumption is stated so you can swap in your own numbers.
Why we don’t give a one-size figure
You’ll see websites quoting a flat “costs X pence an hour” for air conditioning. We don’t, because the real answer depends on:
- how much heating or cooling the room needs, which comes down to its size, insulation, glazing and which way it faces
- how many hours you run it, and at what setting
- what you pay per kWh, which varies by region, tariff and whether you’re on a fixed deal
- the unit’s efficiency, which varies by model, size and outdoor temperature
So instead, here’s the method, with clearly labelled example numbers.
The two numbers you need
1. Your electricity unit rate. For this guide we’ve used the Ofgem energy price cap for 1 October to 31 December 2026: 26.32p per kWh for electricity, paying by direct debit. That’s a Great Britain average. Rates in the North Scotland and South Scotland regions differ slightly, and if you’re on a fixed or time-of-use tariff your rate will be different again. Check your latest bill for your actual figure.
The price cap also sets a daily standing charge (54.83p a day on average for electricity). You pay that whether or not you have air conditioning, so it doesn’t change the running cost of the unit.
2. The unit’s efficiency. The reversible systems we install typically heat at a seasonal efficiency of SCOP 4.0–5.2, depending on model, size and conditions. That means roughly 4 to 5.2 kWh of heat for every 1 kWh of electricity. A plug-in electric heater turns 1 kWh of electricity into 1 kWh of heat (a COP of 1).
The basic sum
To work out the cost of heat:
Cost per kWh of heat = electricity unit rate ÷ efficiency
At 26.32p per kWh:
| Heat source | Efficiency | Cost per kWh of heat |
|---|---|---|
| Plug-in electric heater | 1.0 | 26.3p |
| Air conditioning, lower end | SCOP 4.0 | 6.6p |
| Air conditioning, upper end | SCOP 5.2 | 5.1p |
In other words, for the same warmth, air-to-air uses roughly a quarter to a fifth of the electricity a plug-in heater does.
Illustrative example 1: heating a room
This is an illustration, not a quote or a promise. Your room will be different.
Assumption: a room that needs, on average, 1.5 kW of heat, for 6 hours a day, on around 220 days a year. That’s about 2,000 kWh of heat a year. We’ve picked a round, plausible figure for a well-used room such as a home office, so you can see the method.
Per hour (1.5 kWh of heat):
| Heat source | Electricity used | Cost per hour |
|---|---|---|
| Plug-in heater (COP 1) | 1.5 kWh | 39.5p |
| Air conditioning (SCOP 4.0) | 0.38 kWh | 9.9p |
| Air conditioning (SCOP 5.2) | 0.29 kWh | 7.6p |
Per year (2,000 kWh of heat):
| Heat source | Electricity used | Cost per year |
|---|---|---|
| Plug-in heater (COP 1) | 2,000 kWh | £526 |
| Air conditioning (SCOP 4.0) | 500 kWh | £132 |
| Air conditioning (SCOP 5.2) | 385 kWh | £101 |
On these assumptions, heating that room with air-to-air costs roughly £395 to £425 a year less in electricity than a plug-in heater. Halve the hours and you halve both costs and the difference. Double the heat demand and they double.
Two honest caveats. First, SCOP is a seasonal average: on the coldest days the unit works less efficiently, and on mild days more efficiently. Second, this is electricity cost only. It doesn’t include the cost of the installation, or annual servicing.
Illustrative example 2: cooling a room
Again, an illustration with stated assumptions.
Cooling is usually the smaller bill in Scotland, simply because most homes only need it on warmer days in summer.
Assumption: the unit draws an average of 0.5 kW of electricity while cooling, for 4 hours a day, on 30 days a year.
| Figure | |
|---|---|
| Electricity per hour | 0.5 kWh |
| Cost per hour | 13.2p |
| Electricity per year (4 h × 30 days) | 60 kWh |
| Cost per year | £15.79 |
A plug-in heater comparison doesn’t apply here; a portable air conditioner would be the usual alternative, and those typically use considerably more electricity for the same cooling because the hot exhaust has to be ducted out of a window.
What else affects running costs
Sizing. An undersized unit runs flat out and struggles on the coldest days. An oversized one cycles on and off. Both waste energy. This is why we size every system at a free survey rather than guessing from room size alone.
Settings. Setting a sensible target temperature and letting the unit hold it steadily is generally more efficient than blasting it on and off.
Servicing. Blocked filters and dirty coils make the unit work harder. An annual service keeps it running as it should. Ours is from £120 for a single system, plus £40 for each extra indoor unit — see our air conditioning page.
Your tariff. If you’re on a time-of-use tariff with cheaper hours, running costs could be lower than the figures here. Use your own rate in the sum above.
Where this leaves you
If you’re heating a room with plug-in heaters for a good number of hours a year, air-to-air will use much less electricity to do the same job. If you only need occasional warmth, the electricity saving may not justify the installation cost.
If you’re looking to heat the whole house and your hot water, an air source heat pump is a different system and a different conversation. And if you’re comparing other electric options, see our electric heating page.
Frequently asked questions
How much does air conditioning cost to run per hour?+
It depends on how hard the unit is working. In our illustrative heating example, delivering 1.5 kW of heat costs roughly 7.6p to 9.9p an hour at the October–December 2026 price cap rate of 26.32p per kWh. In our cooling example, a unit averaging 0.5 kW of electricity costs about 13.2p an hour. Your figures will vary with your room and tariff.
Is air conditioning cheaper to run than an electric heater?+
For heating, yes, per unit of warmth. A plug-in heater turns 1 kWh of electricity into 1 kWh of heat. Our systems typically achieve SCOP 4.0–5.2, so they need roughly a quarter to a fifth of the electricity for the same heat. The installation costs much more than a heater, though, so how often you use it matters.
Does air conditioning use a lot of electricity?+
Less than many people expect, because it moves heat rather than making it. A properly sized unit also doesn’t need to run flat out most of the time. The amount it uses depends on the room, the weather, your settings and how many hours you run it. We’ll give you a view on your own home at the free survey.
Why don’t you just give a cost per year?+
Because an honest figure depends on your room, your hours and your tariff, and a single number would be wrong for most people. We’ve shown the method and the assumptions instead, so you can put in your own electricity rate and usage. If you’d like help, we’ll talk it through at your survey.
Will the running costs change when the price cap changes?+
Yes. Ofgem reviews the price cap every three months, so the unit rate we’ve used (26.32p per kWh for October–December 2026) will change. The method stays the same: divide your unit rate by the system’s efficiency to get the cost per kWh of heat.
Get a straight answer
Want to know what air conditioning would cost to run in your home? Book a free survey and we’ll size the system for your room and talk through realistic running costs. Call 01506 894600 or get in touch. Read more about our air conditioning installation service.
Sources
- Ofgem, energy price cap 1 October to 31 December 2026 (electricity 26.32p/kWh, standing charge 54.83p/day, direct debit GB average) — https://www.ofgem.gov.uk/information-consumers/energy-advice-households/energy-price-cap-unit-rates-and-standing-charges
- Ofgem, Get energy price cap standing charges and unit rates by region — https://www.ofgem.gov.uk/information-consumers/energy-advice-households/get-energy-price-cap-standing-charges-and-unit-rates-region