Air Con Running Cost Calculator
See what an air conditioner costs to run per hour, per day and across a UK summer. Pick a typical unit or enter your own wattage, then adjust the price and hours to match your home.
Unit
Per hour
20p
Per day
£1.58
Per summer
£47.38
For the same cooling, a fixed split (~750W) costs about 15p/hour vs a portable's 20p/hour, around 25% less to run. Compare split systems
Estimate only. We assume the compressor runs 75% of the time as a thermostat cycles it. Real cost depends on the room, target temperature and your tariff.
Assumptions
- Electricity price
- 26.32p/kWh, Ofgem price cap, 1 October to 31 December 2026 (Ofgem)
- Duty cycle
- 75% of the time running on a typical day (thermostat cycling); 100% in a heatwave
- Sizing
- 430 BTU/m² at 2.4m ceiling, adjusted for insulation, sun, occupants and electronics, rounded up to 500 BTU
Rates checked 20 September 2026. Check them again before you commit to anything.