What a dehumidifier actually costs to run
Damp windows, musty wardrobes, washing that will not dry indoors. Autumn is when the dehumidifier comes out of the cupboard, and most households have no idea what the real dehumidifier running cost is about to add to the bill.
Here is the short version. Under the energy price cap running from 1 October to 31 December 2026, electricity costs around 26p per kWh on average for direct debit customers, according to Ofgem’s published price cap unit rates. That single number is the whole basis for every dehumidifier running cost estimate in this guide.
We will not pretend a dehumidifier is going to wreck your budget. It will not. Run one sensibly and the dehumidifier running cost is usually smaller than a takeaway coffee a day. Leave it humming away in an empty spare room from September to March, though, and it adds up to real money, the same way leaving the heating on too early does.
How much electricity does a dehumidifier use?
Most household dehumidifiers draw somewhere between 150 and 700 watts, depending on the type and size. That is a wide range. So the honest answer for your dehumidifier running cost is: it depends what is sitting in your utility cupboard, not what the box promised in the shop.
As a rough guide, at around 26p per kWh:
- A small compressor dehumidifier (around 150 to 200W) running for 4 hours costs roughly 16p to 21p.
- A mid-size compressor unit (around 250 to 350W) running for 4 hours costs roughly 26p to 36p.
- A larger desiccant model (around 400 to 700W) running for 4 hours costs roughly 42p to 73p.
Run one of the smaller units for a few hours most days over a damp month, and the dehumidifier running cost typically lands somewhere around £5 to £10. Leave a bigger desiccant model on around the clock and you could be looking at £20 to £30 a month. That is the gap worth knowing before you buy one, and it puts a dehumidifier well down the list of the most expensive appliances to run.
Is it cheaper to run a dehumidifier or turn up the heating?
Usually, a dehumidifier is the cheaper fix for damp air, not the heating. Warm air holds more moisture, so cranking the thermostat to “dry the place out” burns far more energy than pulling the moisture out directly.
A dehumidifier targets the actual problem, the water in the air, rather than trying to out-muscle it with heat that escapes through the nearest draughty window. For condensation on a single room, a couple of hours with a dehumidifier will usually beat an extra hour of central heating on cost.
That said, a dehumidifier will not heat your home. If you are cold as well as damp, you likely need both, just not both running flat out at the same time. A portable electric heater for one cold room can work out cheaper than heating the whole house to fix a problem that is really about moisture.
Compressor vs desiccant: which costs more to run?
Compressor (refrigerant) dehumidifiers are generally the cheaper option to run and work best in warmer rooms, above about 15°C. They are the sensible default for most UK living rooms and bedrooms.
Desiccant dehumidifiers use a heating element to work, so they typically draw more power and cost more per hour. Their advantage is that they keep working in cold spaces like garages, caravans or an unheated spare room, where a compressor model struggles.
If you are buying one purely to manage everyday condensation in a normal, heated home, a compressor model will usually keep your dehumidifier running cost lower for the same job, without the higher wattage a desiccant heater element needs.
Simple ways to cut your dehumidifier running cost
Key takeaways
- Check the wattage on the rating label, not just the tank size, before you buy.
- Use timer or humidistat settings so it switches off once the air is dry, instead of running constantly.
- Close the door of the room you are drying, so it is not pulling moisture from the whole house.
- Empty and clean the tank and filter regularly, a clogged filter makes the unit work harder for longer.
- Pair it with a five-minute blast of ventilation after a shower or cooking, rather than hours of dehumidifying afterwards.
Most of the saving is not about which model you buy. It is about not leaving it humming away in an empty room out of habit. That habit, more than the model, is the quiet, everyday Do-Nothing Default that inflates bills all winter, and Roo would happily tell you so.
The bigger picture on your bill
A dehumidifier running cost of a few pounds a week will not make or break your budget on its own. What actually moves the needle is the rate you are paying for every kWh it uses, on top of everything else in the house.
If you are still on your supplier’s standard variable rate, you are paying the full price cap rate on that electricity, and on every other appliance in the house. Fixing a competitive deal, where one is available, is usually the bigger lever. Pull that one first.
Frequently asked questions about dehumidifier running costs
- How much does it cost to run a dehumidifier for a week?
- Running a small to mid-size dehumidifier for around 4 hours a day for a week typically costs roughly £1 to £2.50, based on the current price cap electricity rate. A larger desiccant model run for longer will cost more.
- Is it worth running a dehumidifier all winter?
- For a genuinely damp room, yes, it is usually worth it, but running it on a timer or humidistat rather than continuously keeps the dehumidifier running cost down without losing the benefit.
- Do dehumidifiers use more electricity than a fridge?
- A dehumidifier draws more power while it is actually running than a modern fridge does on average, but a fridge runs constantly and a dehumidifier usually does not, so the total cost over a week can end up fairly similar depending on use.
- What size dehumidifier do I need for a UK house?
- As a rough guide, a compact model suits a single room, while a larger capacity unit suits a whole flat or persistent damp across several rooms. Checking the manufacturer’s room-size guidance before buying avoids paying for more power than you need.
- Does running a dehumidifier make your home warmer?
- Not really. Some models release a small amount of warm air as a byproduct, but a dehumidifier is not a heater and should not be relied on to warm a room.
Sources: Ofgem’s energy price cap unit rates and standing charges for 1 October to 31 December 2026, checked September 2026.
