- Cost per hour
- £0.23
- Cost per day
- £1.41
- Cost per week
- £9.87
- Cost per month
- £42.89
- Electricity used per month
- 164.25 kWh
Running a 900 W air conditioner for an average of 6 hours a day would cost about £1.41 a day, £9.87 a week and £42.89 a month.
Calculated by SmartMoneyTools.co.uk
Convert the electrical power from watts to kilowatts, multiply it by the average hours used per day, then multiply the resulting kWh by the electricity unit rate.
Example calculation
A 900 W air conditioner has an electrical input of 0.9 kW. Running it for six hours a day uses:
0.9 kW × 6 hours = 5.4 kWh a day
The estimated daily cost is:
5.4 kWh × 26.11p = £1.41 a day
That is about £0.23 per hour, £9.87 per week and £42.89 per month.
The monthly figure is an average based on 365 days divided by 12. Your cost for a calendar month will depend on how many days you use the air conditioner.
The estimate assumes the unit draws its rated power continuously. In practice, the compressor may cycle off after the room cools, so actual consumption can be lower.
This estimate does not include:
- Purchase price or installation
- Room size or cooling performance
- Efficiency ratings
- Standing charges
- Where can I find my air conditioner's wattage?
Check the product label or manual first. Electrical input may be shown in watts (W) or kilowatts (kW); multiply kilowatts by 1,000 to get watts.
If the electrical wattage is not available, the BTU shortcuts below the electrical power input provide an editable estimate.
- Is BTU the same as wattage?
- No. BTU means British thermal unit and describes cooling capacity, while electrical wattage describes the power the appliance draws. The presets use rounded wattage assumptions, not a direct conversion, and you can replace them with the model's actual electrical input.
- Why might my actual running cost be different?
- Room conditions and how you use the appliance affect actual electricity use. Temperature setting, insulation, open windows and weather can change how often the compressor runs, while the electrical input may also differ from the rounded BTU preset.
- Is an air conditioner more expensive to run than a fan?
A portable air conditioner normally costs more to run than a fan because it powers a compressor as well as fans. At 26.11p per kWh, a 50 W fan used for six hours costs about £0.08 a day, compared with about £1.41 a day for the 900 W air conditioner in the example.
A fan moves air but does not provide the same cooling effect.
- Which electricity unit rate should I use?
- Use the price in pence per kilowatt hour (p/kWh) on your electricity bill or tariff details. Enter it in the unit rate input. Rates vary by tariff and region, so the figure from your bill gives a more accurate result than the Ofgem Great Britain average.
- Can I compare my air conditioner with other appliances?
- Use the Electricity Cost Calculator to add your portable air conditioner alongside a fan, dehumidifier or another appliance. Enter a separate wattage and daily running time for each one to see its running cost and the combined daily, monthly and yearly totals.
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