Air conditioning running cost calculator
Estimate what your air conditioner costs to run for summer cooling or winter heating. Use your electricity tariff and the hours and days you expect to use it.
Estimated annual cooling cost
£16.926 hours a day for 60 cooling days
- Per hour of use
- 4.7p
- Per cooling day
- 28.2p
- Electricity per year
- 64.3 kWh
How daily hours change your bill
Compare yearly costs at the same tariff and number of cooling days. Select a bar to try that schedule.
How much does air con cost to run in the UK?
A 2.5 kW split system with a cooling efficiency (SEER) of 7, working at 50% load, costs about 4.7p per hour at 26.32p/kWh. At 6 hours a day for 60 days, that comes to £16.92 a year for cooling.
What about heating in winter?
For example, a reversible system with 3.2 kW of heating capacity, 50% average load and a seasonal heating efficiency (SCOP) of 4 uses about 0.4 kWh per hour. At 26.32p/kWh, that’s 10.5p per hour or £101.07 for 120 heating days at 8 hours per day. Adjust the example to match how you heat your home.
The starting tariff is Ofgem’s October–December 2026 average direct-debit electricity rate for Great Britain. Your rate may differ. Use your own bill, including in Northern Ireland.
How is the estimate calculated?
Multiply the system’s rated output by its average load fraction. Divide by the cooling efficiency (SEER) for summer or the average-climate heating efficiency (SCOP) for winter. A SCOP of 4 means each kWh of electricity delivers about 4 kWh of heat over the standard heating season. How to read the air conditioner energy label.
For known wattage, divide average input watts by 1,000. Multiply by operating hours, days of use and the price per kWh in pounds.
Does a 2.5 kW air conditioner draw 2.5 kW?
That rating usually describes the heat the unit can remove. Actual electricity use depends on efficiency and load. For example, the cooling example averages about 179 watts of electrical input under those assumptions. The seasonal efficiency method averages performance across test conditions.
What changes my actual bill?
Outdoor temperature, insulation, thermostat setting and how long the compressor runs all affect consumption. Winter performance varies with the weather and heat lost from the room. Each estimate covers the selected mode at one electricity rate. It excludes fixed standing charges, installation and servicing.
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