Calculator
Running-cost calculator
Enter the wattage and hours for up to three appliances and the unit rate from your bill. For a tumble dryer you can enter the kWh per cycle from its energy label instead.
In short
kWh = watts x hours ÷ 1,000. Multiply the kWh by your unit rate in pence per kWh to get the cost of one session, then by sessions per week x 52 ÷ 12 for a month.
Compare three appliances
The dehumidifier and airer figures are examples: replace them with the wattage on your own appliance. Per month = per session x sessions per week x 52 ÷ 12. Rounded to 0.01 kWh and 0.1 p.
How it works
An appliance rated at 220 W running for 6 hours uses 220 x 6 ÷ 1,000 = 1.32 kWh. Multiply that by the unit rate on your bill to get the cost in pence. The wattage on a dehumidifier listing is usually the maximum; a unit with a humidistat cycles off once the room reaches the target, so the real figure is often lower.
Tumble dryers are labelled in kWh per cycle rather than watts, so the calculator lets you enter that figure straight from the energy label.
| Watts | Hours | kWh per session |
|---|---|---|
| 160 | 8 | 1.28 |
| 220 | 6 | 1.32 |
| 300 | 8 | 2.40 |
| 650 | 4 | 2.60 |