Costs
How much does air conditioning cost to run?
How to estimate the running cost of home air conditioning for cooling and heating, worked examples, and practical ways to keep the bills down.
Last reviewed 2 min read
How to work it out
Running cost is the electricity the system uses, multiplied by your electricity rate:
Cost = power drawn (kW) × hours running × your electricity rate (per kWh)
Modern inverter systems draw the most power when they first start, then slow down once the room is at temperature. That means the average power draw is usually well below the maximum on the spec sheet.
Example: cooling a bedroom
A typical 2.5 kW bedroom unit might draw around 0.5 kW on average once the room has cooled. At an example rate of 25p per kWh, that’s about 12.5p an hour, or around 50p for a four-hour evening. Your costs will differ with your tariff, the weather, the room and the setting you choose.
Heating compared with other options
When heating, air conditioning gives out several units of heat for each unit of electricity it uses. That efficiency is shown as SCOP, which our guide to heating with air conditioning explains.
| Heat source | Example cost per kWh of heat |
|---|---|
| Air conditioning, SCOP 4 | About 6p |
| Air conditioning, SCOP 3 | About 8p |
| Modern gas boiler, 90% efficient | About 7p |
| Older gas boiler, 75% efficient | About 8p |
| Plug-in electric heater | About 25p |
These figures use example rates of 25p per kWh for electricity and 6p per kWh for gas, and leave out standing charges. Swap in the rates from your own bill to compare.
Keeping running costs down
- Choose a unit with high efficiency ratings (SEER and SCOP), and one sized properly for the room.
- Set a sensible temperature. In summer, a few degrees below the outside temperature is often enough to feel comfortable.
- Leave it running steadily at a moderate setting rather than switching on and off at maximum.
- Keep doors and windows closed, and close curtains on sunny windows in summer.
- Clean the filters regularly. Our servicing guide explains how.
- Look at time-of-use tariffs if you can run the system at off-peak times.
Common questions
- Is air conditioning expensive to run in the UK?
- For occasional cooling of one or two rooms, running costs are usually modest. Using the example rate of 25p per kWh, a bedroom unit costs around 50p for a four-hour evening. Costs rise with the number of rooms, hours of use and your tariff.
- Is it cheaper to heat with air conditioning or an electric heater?
- Air conditioning is much cheaper. A system with a SCOP of 4 uses about a quarter of the electricity of a plug-in electric heater for the same amount of heat.
This guide is general information, not professional planning, electrical or financial advice. Check the details for your property with the council and a qualified installer.