Dehumidifier Running Costs UK 2026: From 5p an Hour

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Every October the same worry surfaces in UK households: the windows start streaming, a dark patch appears behind the wardrobe, and someone suggests buying a dehumidifier. Then comes the hesitation. Is it going to cost a fortune to run all winter?

The short answer is no, and by a wider margin than most people expect. A typical 200W compressor dehumidifier costs around 5p an hour to run, and because the humidistat switches it off whenever the room hits its target humidity, a realistic bill across an entire damp season is closer to £31 than the £100-plus figure people fear.

This guide shows exactly where those numbers come from, what changes them, and the three comparisons that actually matter: a dehumidifier against a tumble dryer, against a heated airer, and against simply turning the heating up.

What electricity rate this guide uses

All the figures below use 26.32p per kWh, the electricity unit rate under the Ofgem energy price cap for 1 October to 31 December 2026. That is the rate that will apply through the start of the damp season, so it is the honest one to use for a guide about autumn and winter running costs.

Two things are worth knowing before the sums. First, there is no VAT on electricity from 1 October 2026 to 31 March 2027, so that 26.32p is what you actually pay per unit. Second, the daily standing charge of 54.83p is a fixed cost of having an electricity supply at all - it does not change whether the dehumidifier is on or off, so it plays no part in these calculations. If you are on a fixed tariff or a time-of-use tariff your rate will differ, and the method below still works. Just swap your own pence-per-kWh figure into the sum.

How much does a dehumidifier cost to run per hour?

Every appliance running cost is the same three-part sum:

Power in kilowatts, multiplied by hours running, multiplied by your unit rate.

The only variable that catches people out is the power rating, because dehumidifiers span an enormous range. A wardrobe-sized Peltier unit draws 40W. A large desiccant model draws 650W - sixteen times as much. Here is what that means in pence.

The 200W to 300W band covers the vast majority of dehumidifiers sold to UK households, which is why the headline answer to this question is roughly 5p to 8p an hour.

If you want your own machine's real draw rather than the plate rating, a plug-in energy monitor sits between the plug and the socket and reports actual kWh over a real session. For dehumidifiers this is more revealing than for most appliances, for a reason we come to next.

Why "watts times hours" overstates your real bill

Here is the thing almost every dehumidifier running cost article gets wrong, and it is the single biggest reason people overestimate the bill.

A dehumidifier is not like a heater or a kettle. It has a humidistat: you set a target relative humidity, and once the room reaches it, the compressor shuts down. The fan may keep turning over, but the part that draws the power stops. It fires up again only when humidity climbs back past the threshold.

So the "eight hours at 300W" arithmetic that fills most comparison tables describes a worst case that almost never happens outside the first day or two of use. In a typical UK room, once the initial moisture load is pulled out, a dehumidifier settles into a duty cycle of roughly 30% to 50% - meaning that in an eight-hour run, the compressor is genuinely working for perhaps three or four of those hours.

That distinction transforms the monthly numbers.

Roughly £31 to £46 to keep a room dry for an entire autumn and winter is a very different proposition from the £77 to £115 the nameplate maths implies. The duty cycle is doing the work, and it is why setting the target humidity sensibly matters so much - which we cover further down.

A useful cross-check is cost per litre of water removed. Modern compressor units extract at roughly 0.3 kWh per litre in real conditions, which works out at about 7.9p per litre at the October 2026 rate. If your machine is filling a 2-litre tank a day, you are spending about 16p a day on it.

Compressor vs desiccant: which is cheaper to run?

Domestic dehumidifiers come in two technologies, and the running cost gap between them is large.

A compressor (or refrigerant) dehumidifier chills a coil below the dew point so moisture condenses onto it and drips into the tank. It is essentially a fridge that throws away the cold. Domestic models draw 160W to 480W and are the cheapest type to run, but their efficiency falls away as the room gets colder, because there is less moisture in cold air for them to grab. Below roughly 15°C they start to struggle.

A desiccant dehumidifier passes air over an absorbent wheel and then uses a heater to drive the collected moisture back out of it. That regeneration heater is why desiccants draw 550W to 700W, roughly three times a comparable compressor. In exchange they work perfectly well down to a few degrees above freezing, and they exhaust noticeably warmer air.

For most people dehumidifying a normally heated home, a compressor dehumidifier is the right call and roughly a third of the running cost. Buy a desiccant dehumidifier only if you genuinely need to dry an unheated space - a garage, a caravan, a cold utility room, a holiday home over winter - where a compressor would barely function.

What size do you actually need?

Capacity is quoted in litres extracted per day, and there is a trap in the number.

The trap: rated extraction is measured in laboratory conditions of around 30°C and 80% relative humidity. A British bedroom in November at 18°C and 65% humidity is nowhere near that, so a 20 litre machine will not pull 20 litres out of your house. Expect something in the region of a third to a half of the rated figure in real domestic conditions. This is not a fault or false advertising, it is a standardised test condition - but it does mean undersizing is the more common mistake, and an undersized unit running flat out all day costs more than a larger one cycling comfortably.

Those tiny 40W Peltier units deserve a specific warning. They extract 250ml to 500ml a day at best. They are genuinely useful in a wardrobe or a small cupboard, and completely useless against a damp room, whatever the listing claims.

Dehumidifier vs tumble dryer vs heated airer for drying washing

This is the comparison most people are really after in winter, and it is the one competitors handle worst - usually because they leave the heat pump tumble dryer out entirely.

Drying a load of washing indoors puts two to three litres of water into your air. That water has to go somewhere. Either it condenses on your coldest wall, or you remove it. Here is what each method costs for the same load, at 26.32p per kWh.

Three things fall out of that table.

A dehumidifier is a genuine drying appliance, not just a damp fix. An ordinary unheated airer with a dehumidifier running beside it dries a load for about 39p - cheaper than every tumble dryer including a heat pump model, and it removes the moisture rather than pushing it into your walls.

The airer-plus-dehumidifier combination costs the same as the dehumidifier alone. Adding a covered heated airer speeds the load up from five hours to three, and because both machines run for less time the total lands in the same place. You get the washing dry sooner for no extra money.

A condenser dryer is still the most expensive way to dry clothes in Britain. At £1.47 a load, five loads a week comes to £383 a year. The same washing dried on an airer with a dehumidifier runs to about £103. We break the dryer side of this down properly in our tumble dryer running costs guide, and the airer side in our heated airer running costs guide.

Most mid-range dehumidifiers have a laundry mode that runs the fan harder and drives the target humidity lower, typically to around 35%. It costs a little more per hour while active, and most models cut out automatically after six hours. It is worth using - drying clothes in a room at 35% humidity is dramatically faster than at 60%.

Is a dehumidifier cheaper than heating the room?

Yes, and it is not close.

A 2kW plug-in electric heater costs roughly ten times as much per hour as a mid-size dehumidifier (the full breakdown by heater type is in our electric heater running costs guide). If the problem you are solving is condensation on the windows or a damp patch behind furniture, reaching for a heater is the expensive answer to the wrong question. Cold air holds less moisture, so heating a room does reduce condensation - but you are paying central-heating money to achieve what a 5p-an-hour appliance does directly. Our guide to stopping condensation on windows sets out the cheaper levers to try first.

Where the same logic applies at scale is the fabric of the house. Cold external walls are where condensation lands, and warming those surfaces permanently costs far less than running heaters at them. Our guides to cavity wall insulation costs and draught proofing cover the fixes that reduce the condensation load in the first place, and the home insulation guide puts them in order of payback.

Will a dehumidifier cut my heating bill?

You will see this claim everywhere: dry air heats up faster, so a dehumidifier pays for itself in reduced heating. Treat it with scepticism.

The comfort effect is real. Damp air pulls heat away from your skin faster than dry air, so a room at 19°C and 45% humidity genuinely feels warmer than the same room at 19°C and 70% humidity. Many people find they can turn the thermostat down a degree once the humidity is under control, and a degree is worth real money over a winter.

The bill effect is where the claim falls apart. A two-week real-world test on a 20 litre, 219W dehumidifier running continuously found that heating hours roughly halved, from 46 hours to 22 - but the total energy bill for the fortnight went up, from £12.34 to £23.08. The dehumidifier used more electricity than the heating it displaced.

So the honest framing is this: a dehumidifier buys you comfort, dry walls and dry washing for a modest and predictable cost. It does not buy you a lower energy bill. Anyone selling you one on the promise of heating savings is overstating the case.

If you want to see the effect on your own usage rather than take anyone's word for it, watch your in-home display for the hour after you switch a dehumidifier on. This is the same visibility benefit we describe in our guide to whether smart meters save you money - the numbers are usually far smaller than people brace for. To model where the rest of your electricity is going, try our smart meter savings calculator.

The energy rating myth

Here is something worth knowing before you shop: dehumidifiers carry no official UK or EU energy label.

You will see listings advertising A++ or A+++ dehumidifiers. Those badges are manufacturer marketing, not a regulated rating. Dehumidifiers are excluded from the EU energy labelling framework and from the Ecodesign requirements that govern fridges, washing machines and tumble dryers, and no UK equivalent has replaced them. There is no independently verified efficiency class to compare between models.

What that means in practice is that the only reliable efficiency figures are the ones on the specification sheet: the power rating in watts, and the extraction capacity in litres per day at the stated test conditions. Divide one by the other and you have a rough efficiency comparison that is real. Ignore the letter grades.

How to cut your dehumidifier running costs

Set the target humidity to 50 to 55%, not lower. This is by far the biggest lever. Every percentage point below about 50% makes the machine work disproportionately harder for no health or comfort benefit. The 30% to 50% duty cycle that makes dehumidifiers cheap to run only happens if the target is achievable.

Close the door of the room you are drying. A dehumidifier fighting the moisture of an entire house through an open door never reaches its target and never cycles off. Shut the door and it will be off within a couple of hours.

Use a hygrometer to check whether you need it on at all. A cheap humidity monitor costs a few pounds and tells you the actual relative humidity in each room. Plenty of people run a dehumidifier in a room that was already at 48%.

Empty the tank or plumb in continuous drainage. A full tank stops the machine, and on some models it stops it in a state that still draws standby power. Most units accept a hose for continuous drainage, which is worth setting up if you are running one all season.

Buy for the space, then run it less. An undersized unit running flat out for twelve hours costs more than a larger one cycling for four. This is the opposite of the usual energy advice, and it is specific to appliances with a humidistat.

Keep the filter clean. A blocked filter restricts airflow and forces longer run times for the same extraction. Most are a rinse under the tap once a month.

Do not use it as a heater. The exhaust air is warmer, especially on a desiccant model, and it is tempting to treat that as free heating. It is not free, it is just electricity, and a dehumidifier is a poor and expensive way to convert electricity into warmth compared with an actual heater.

The cost of not using one

Running costs only mean something in context, and the context here is what damp does if it is left alone.

Persistent damp and mould are a recognised health risk, not merely a decorating problem. The UK government's guidance for housing providers sets out the respiratory risks in detail, and the law has hardened considerably since. Phase 1 of Awaab's Law came into force on 27 October 2025 in England, requiring social landlords to investigate significant damp and mould hazards within 10 working days, provide a written summary to the tenant within 3 working days of concluding that investigation, and begin remedial work within 5 working days. Emergency hazards must be investigated and acted on within 24 hours. Phase 2 extends the same regime to a wider set of housing hazards from 30 November 2026.

If you rent from a social landlord and have damp or mould, that is a legal duty owed to you, and a dehumidifier is a stopgap rather than a substitute for reporting it.

For owner-occupiers the arithmetic is simpler. Washing down and repainting a mould-affected bedroom wall typically runs into the low hundreds of pounds. A professional damp survey costs £150 to £300 before any work is done. Replacing a mattress, a wardrobe or a carpet ruined by mould costs considerably more than that. Against a season of dehumidifier running at £31 to £46, the case makes itself - provided the damp is condensation, which is what a dehumidifier addresses. Rising damp and penetrating damp are structural faults and no dehumidifier will fix them. If the damp patch is at floor level, or appears after rain rather than after cooking and showering, get it surveyed.

Frequently asked questions

How much does a dehumidifier cost to run per hour in the UK? A typical 200W compressor dehumidifier costs about 5.3p an hour at the October 2026 price cap rate of 26.32p per kWh. A larger 300W unit costs 7.9p an hour, and a 650W desiccant model costs 17.1p an hour.

How much does it cost to run a dehumidifier all day? Running a 200W dehumidifier continuously for 24 hours would cost £1.26, but that almost never happens. The humidistat switches the compressor off once the room reaches its target humidity, so a realistic full day costs 40p to 60p once the room has dried out.

Is a dehumidifier cheaper than a tumble dryer? Yes. An unheated airer with a dehumidifier running beside it dries a load of washing for about 39p, against 99p for a vented tumble dryer and £1.47 for a condenser. Only a heat pump tumble dryer comes close, at around 53p a load.

Is it cheaper to run a dehumidifier or the heating? A dehumidifier is around ten times cheaper per hour than a 2kW plug-in electric heater. If your goal is to stop condensation rather than to warm the room, the dehumidifier is the far cheaper tool.

Do dehumidifiers use a lot of electricity? No. A mid-size dehumidifier draws about the same as two or three laptops. Across a full damp season from October to March, running one for eight hours a day typically costs £31 to £46 in total.

Should I leave a dehumidifier on all the time? There is no need. Set it to a target of 50 to 55% relative humidity and let the humidistat decide. It will run hard for the first day or two and then cycle on and off for a fraction of the time, which is exactly what keeps the running cost low.

Compressor or desiccant, which should I buy? For a normally heated home, a compressor model, because it costs roughly a third as much to run. Choose a desiccant only for genuinely cold spaces such as a garage, conservatory or unheated utility room, where a compressor would barely extract anything.