Dehumidifier Running Cost Calculator UK
Enter your dehumidifier wattage and runtime to estimate cost per session, week, month and year. The default electricity rate is refreshed from the current UK rate source when available, and you can replace it with your own tariff.
Use the power for your appliance and the time it actually runs. This estimates a continuous draw; use measured kWh when you have it.
Formula: watts ÷ 1,000 × hours × electricity rate. The rate is in pence, and results are shown in pounds. Monthly = weekly × 52 ÷ 12; annual = weekly × 52. Standing charges are excluded.
How much does a dehumidifier cost to run?
The calculator above uses 26.32p/kWh as its current default electricity rate. Change the rate in the calculator if your tariff is different.
Worked examples at the current default rate
| Example | Energy | Estimated cost | Cost per hour |
|---|---|---|---|
| 150W for 4 hours | 0.60 kWh | 15.8p | 3.9p |
| 250W for 8 hours | 2.00 kWh | 52.6p | 6.6p |
| 350W for 8 hours | 2.80 kWh | 73.7p | 9.2p |
| 500W for 8 hours | 4.00 kWh | £1.05 | 13.2p |
These are calculation examples, not claims about what every dehumidifier will consume. Actual draw can fall when a compressor cycles off or changes mode.
Rated watts vs real electricity use
A label showing 250W means the appliance can draw around that level when operating, not that it will necessarily consume 250W continuously for every hour you leave it switched on. Compressor models can cycle as the target humidity is approached, so a plug-in energy monitor gives a better measured estimate than nameplate watts alone.
Price a measured session instead of guessing the running time
If you already have a suitable energy-monitor reading for a completed session, choose the calculator’s kWh input and enter that energy directly. Use a monitor only where the appliance manufacturer allows it. Do not multiply the reading by hours again.
For an arithmetic example, 1.25 kWh at the default rate above costs £0.33. This is an input example, not a measured drying test or a promise about your appliance. For laundry, use the same load size and final dryness when comparing methods.
Cost per hour is not the whole decision
A low hourly cost can still become expensive if the appliance has to run for much longer. For laundry, compare the cost per completed load. For condensation, compare the cost of reaching and maintaining a sensible humidity level rather than simply comparing wattage.
Useful next steps
What the result means
- Cost is calculated from watts, runtime and electricity unit rate — not from the litres-per-day extraction rating.
- Compressor models can cycle as the target humidity is approached, so nameplate wattage may overstate measured consumption over a long session.
- For the best real-world estimate, use the appliance label for a quick calculation or a plug-in energy monitor for measured consumption.
- Standing charges are excluded because using the dehumidifier does not create an additional daily standing charge.
Related guides
Read more about the topics covered by this calculator: