Small desiccant dehumidifier (250W)
0.25 kWh × 27p = 6.75p per hour
8 hours/day: 54p
Per month (8h/day): £16.20
UK running costs guide
How much does a dehumidifier cost to run in the UK? 2026 rates
Dehumidifier running costs range from around 4p to 17p per hour in the UK, depending on the model, its wattage and your electricity tariff. Here is what determines the cost and how to work it out for your specific situation.
UK guide
The cost is usually lower than people expect
Running a dehumidifier for 8 hours a day costs between 32p and £1.36 — less than a bar heater, and far less than a tumble dryer.
Quick answer — the cost range
Under the April 2026 UK energy price cap, a typical UK household pays approximately 24p–34p per kWh including VAT. On this rate:
Medium compressor dehumidifier (450W)
0.45 kWh × 27p = 12.15p per hour
8 hours/day: 97p
Per month (8h/day): £29.10
Large compressor dehumidifier (650W)
0.65 kWh × 27p = 17.55p per hour
8 hours/day: £1.40
Per month (8h/day): £42.00
These are approximate ranges using the Ofgem price cap rate for April 2026 (27p/kWh standard tariff, including VAT). If you are on a fixed-rate tariff, your cost per kWh may be lower — check your energy bill.
The formula — how to calculate it yourself
The running cost formula is straightforward:
Watts × hours × kWh rate ÷ 1,000 = cost
Example: 450W dehumidifier running 6 hours = 450 × 6 ÷ 1,000 = 2.7 kWh × 27p = 73p
Example: 450W dehumidifier running 6 hours = 450 × 6 ÷ 1,000 = 2.7 kWh × 27p = 73p
Or use our free calculator — enter your dehumidifier's wattage, how many hours you run it, and your tariff rate:
What affects how much your dehumidifier costs to run?
Wattage — the biggest factor
Desiccant dehumidifiers typically draw 250–350W. Compressor dehumidifiers typically draw 300–700W depending on capacity. Choosing the right size for your room matters: a dehumidifier that is too small runs constantly and never switches off, costing more than a correctly sized unit.
Your electricity tariff
The Ofgem price cap for April 2026 is approximately 27p/kWh for standard variable tariffs. If you are on a fixed-rate deal you may pay 20–25p/kWh. Economy 7 or time-of-use tariffs can reduce costs to 10–15p/kWh during off-peak night hours.
How long you run it
Most rooms reach target humidity (50–55%) within 2–4 hours once the dehumidifier is correctly sized. Running it continuously after that wastes energy — a dehumidifier with a humidistat will then cycle on and off automatically to maintain the target level.
Room conditions
A colder room reduces the efficiency of compressor dehumidifiers — the coil needs warmth to evaporate the collected moisture. Desiccant dehumidifiers maintain efficiency in cold rooms (below 15°C), which makes them a better choice for unheated bedrooms or garages in winter.
Season
UK winters create more condensation (cold walls, windows kept closed) so dehumidifiers work harder. Summer humidity is often lower indoors, reducing running time and cost. Autumn and winter are typically when dehumidifiers run most and cost the most.
How drafty the room is
A room that loses moisture quickly (open windows, draughty doors, extractor fans pulling air out) means the dehumidifier runs longer. Sealing obvious drafts and closing doors when the dehumidifier is running reduces running time and cost.
Desiccant vs compressor — which costs less to run?
There are two main types of dehumidifier, and they work differently:
Compressor dehumidifiers
Work like a refrigerator — a compressor pumps refrigerant through a coil to condense moisture from the air. More energy-efficient at moisture removal in warm conditions. Better for: living rooms, kitchens, bathrooms where temperatures are typically above 15–20°C. Typical wattage: 300–700W.
Running cost: 8–17p per hour depending on wattage.
Desiccant dehumidifiers
Use a silica gel desiccant wheel to absorb moisture from the air, then heat it to release the moisture into a collection tank. Less efficient in terms of energy per litre of water removed, but maintain effectiveness in cold temperatures. Better for: bedrooms, unheated rooms, garages, boats, caravans. Typical wattage: 250–650W.
Running cost: 5–15p per hour depending on wattage.
Is it worth running a dehumidifier every day?
For most UK homes with condensation or mould problems, running a dehumidifier daily during winter is effective and the cost is reasonable:
- A medium compressor dehumidifier running 6 hours a day costs roughly £1.80–£2.20 per week
- A small desiccant dehumidifier running 6 hours a day costs roughly 60p–90p per week
- The alternative — treating mould repeatedly or calling in a professional damp treatment — costs £150–£500+
- Running a dehumidifier to prevent condensation mould is significantly cheaper than the health and property costs of unaddressed damp
During summer or in well-ventilated homes, you may only need to run the dehumidifier occasionally. A hygrometer (from £10) helps you check whether you need it running.
How to cut your dehumidifier running costs
- Size it correctly. The most common mistake is buying too small a unit. A dehumidifier that is too small runs constantly and never fully dries the room. Use our dehumidifier size calculator to pick the right capacity.
- Use the humidistat. Set your target humidity to 50–55%. Once reached, the dehumidifier cycles on and off automatically rather than running continuously.
- Run it in the afternoon. After a morning of closed windows and condensation, afternoon is when humidity peaks. Running the dehumidifier 2–6 hours in the afternoon and evening is most effective.
- Close doors. Keep the dehumidifier in one room with the door closed so it is not fighting humidity from the rest of the house.
- Fix the ventilation first. A dehumidifier removes moisture that is already there. Improving ventilation (opening windows, using extractor fans) prevents moisture building up in the first place, reducing how hard the dehumidifier has to work.
- Compare tariffs. Switching from a standard variable tariff to a fixed deal could save 5–10% on your dehumidifier running costs. Use a comparison site to check deals.
Tools
Dehumidifier running cost calculator
Enter your model's wattage and your electricity tariff rate to see exact daily, weekly and monthly costs.
Dehumidifier size calculator
Enter your room dimensions and dampness level to find the right capacity dehumidifier. Right-sizing reduces running costs.
Mould removal guide
If condensation is causing black mould, this step-by-step guide covers safe removal and prevention.
Energy rates: Ofgem Default Tariff Cap Rate April 2026: approximately 27p/kWh including VAT for standard variable tariffs. Rates vary by region and payment method (direct debit typically cheapest). Fixed tariff rates vary — check your latest energy bill for your actual p/kWh figure.