Most home compressor dehumidifiers draw about 105–270 W, which costs 2.8p to 7.0p an hour at 26.32p per kWh. Desiccant models draw about 350–660 W, or 9.2p to 17.4p an hour.
Which? says the dehumidifiers it has tested cost from about 3p to 17p an hour at full power. Running a typical 150 W compressor model for eight hours costs about 31.6p.
Compressor or desiccant: why the wattage differs
A compressor (or refrigerant) dehumidifier works like a small fridge. It chills a coil, and moisture in the air condenses on it and drips into the tank. A desiccant model passes air over an absorbent wheel, then uses a heater to dry the wheel out, and the heater is why it uses more electricity. According to Which?, compressor models are the more popular choice in the UK, but they struggle in cold spaces. That's why desiccants are usually suggested for unheated garages, conservatories and outbuildings.
| Type | Typical power | Per hour | 8 hours | 24 hours |
|---|---|---|---|---|
| Compressor | 105–267 W | 2.8p – 7.0p | 22.1p – 56.2p | 66.3p – £1.69 |
| Desiccant | 350–660 W | 9.2p – 17.4p | 73.7p – £1.39 | £2.21 – £4.17 |
These are upper estimates. Most dehumidifiers have a humidistat: once the air reaches the humidity you set, a compressor model stops its compressor and a desiccant model turns its heater down. Over a day, the average draw is often well below the rating.
Cost per litre: the fairer comparison
A cheap hour isn't the whole story, because what you're paying for is water out of the air. We used Meaco's published power and extraction figures for two popular models to work out the cost of each litre removed if the machine ran flat out for 24 hours.
| Model | Room | Power | Per hour | 24 hours | Water a day | Cost per litre |
|---|---|---|---|---|---|---|
| Meaco Arete One 10L (compressor) | 20°C, 60% RH | 151 W | 4.0p | 95.4p | 4.34 L | 22.0p |
| Meaco Arete One 10L (compressor) | 10°C, 60% RH | 129 W | 3.4p | 81.5p | 1.41 L | 57.8p |
| Meaco DD8L Zambezi (desiccant), fan speed 1 | 20°C, 60% RH | 351 W | 9.2p | £2.22 | 3.9 L | 56.9p |
| Meaco DD8L Zambezi (desiccant), fan speed 2 | 20°C, 60% RH | 656 W | 17.3p | £4.14 | 8.0 L | 51.8p |
| Meaco DD8L Zambezi (desiccant), fan speed 2 | 10°C, 60% RH | 656 W | 17.3p | £4.14 | 6.6 L | 62.8p |
In a heated room, the compressor model removes water for well under half the cost a litre. In a cold room at 10°C, its extraction drops sharply while the desiccant keeps going, so the costs per litre end up much closer. Which?'s own lab results for its top-rated dehumidifiers range from about 15p to 53p a litre at the same 26.32p rate.
Worked examples
1. Keeping a damp bedroom in check
A 151 W compressor dehumidifier runs for eight hours a day, every day, at full power. It uses 1.208 kWh a day, which costs 31.8p a day, £2.23 a week and about £9.64 a month. With the humidistat cutting in, the real cost should be lower.
2. Drying a load of washing indoors
Say a 216 W compressor model (one of the running-watt figures in Meaco's comparison table) runs for six hours beside a clothes airer. That's 1.296 kWh, or about 34.1p. The average condenser tumble dryer in Which?'s tests works out at about 89.0p a load (see our tumble dryer guide). The six hours is an assumption, since drying time depends on the load, the room and the fabric.
3. A cold garage
A desiccant dehumidifier on 656 W for four hours a day uses 2.624 kWh, which costs 69.1p a day or about £20.72 over 30 days. Some of that electricity comes back as warmth, which helps in a cold space.
Ways to cut the cost
- Set the humidistat, rather than running on continuous. Meaco suggests that setting a target of around 60% RH keeps running time down.
- Close doors and windows while it runs, so it isn't drying the whole street. Which? gives the same advice.
- Keep the filter clean and leave space around the machine so air can flow, unless the manual says otherwise.
- Use the timer to run it when you need it, or on a cheaper off-peak rate if your tariff has one.
How we worked this out
- Price: 26.32p per kWh, Ofgem price cap 1 October to 31 December 2026 (GB average, Direct Debit). The standing charge isn't included.
- Formula: cost = watts ÷ 1,000 × hours × p/kWh. Cost per litre = 24-hour cost ÷ litres extracted a day, using the manufacturer's figures for the same conditions.
- Ranges: compressor 105–267 W from Meaco's published running watts. Desiccant 350–660 W from the Meaco DD8L Zambezi specification, cross-checked against Energy Savers (300–700 W) and Which?'s 3p–17p an hour.
- Run times in the worked examples are illustrative assumptions. We haven't measured any dehumidifiers ourselves.
Frequently asked questions
Is it expensive to leave a dehumidifier on 24/7?
Not usually. A 151 W compressor model running non-stop uses about 3.6 kWh a day, which costs 95.4p a day or about £28.62 over 30 days. A humidistat will cut that once the air is dry enough. A 656 W desiccant model on full would cost £4.14 a day.
Is a dehumidifier cheaper than a tumble dryer for drying clothes?
Usually, yes. In our example, a 216 W compressor model running for six hours costs about 34.1p, against an average of about 89.0p a load for a condenser tumble dryer on Which?'s figures. It's slower, though.
Should I choose a compressor or desiccant dehumidifier?
For a heated home, a compressor model is usually cheaper to run per litre of water removed. For cold spaces such as garages, conservatories or unheated rooms, a desiccant model keeps working where a compressor struggles, and it gives off some warmth.
Does a dehumidifier warm the room?
A desiccant model does noticeably, because it has a heater inside. A compressor model gives off a little warmth from its motor and coils, but much less.
How many hours a day should I run a dehumidifier?
There isn't one right answer. It depends on how damp the room is. Set the humidistat to your target humidity and let the machine switch itself off when it gets there, rather than guessing at a number of hours.
Sources
All checked on 29 October 2026. Figures are restated in our own words; follow the links for the originals.
- Meaco – MeacoDry Arete One 10L specifications: https://www.meaco.com/products/meacodryarete1-10l
- Meaco – DD8L Zambezi desiccant dehumidifier specifications: https://www.meaco.com/products/meaco-dd8l-zambezi-dehumidifier
- Meaco – Meaco dehumidifiers compared: https://www.meaco.ie/meaco-dehumidifiers-compared/
- Meaco blog – When to choose a desiccant dehumidifier: https://blog.meaco.com/when-you-should-consider-choosing-a-desiccant-dehumidifier-instead-of-a-compressor/
- Which? – Best dehumidifiers 2026 (20 Oct 2026): https://www.which.co.uk/reviews/dehumidifiers/article/how-to-buy-the-best-dehumidifier-ay5gu4q77WQN
- Energy Savers (Centre for Sustainable Energy) – How much electricity am I using?: https://www.energysavers.org.uk/advice/electricity-usage/
- Ofgem – Energy price cap unit rates and standing charges: https://www.ofgem.gov.uk/your-energy-supply/your-energy-bill/energy-price-cap-unit-rates-and-standing-charges