How to stop condensation on windows — even every morning
Why bedroom windows are wet every morning, what to do straight away, and the fixes that stop condensation on windows for good in UK homes.
Dehumidifiers · Humidity · Condensation · Laundry
Dehumidifier, humidity and condensation help for UK homes
Stop wet windows and mould, dry washing indoors without the damp, and choose a dehumidifier that suits your rooms, your heating and your energy bill — in plain English, for the way British homes are actually built.
- Written for UK homes and current UK energy prices
- No fake reviews, made-up ratings or "we tested" claims
- Free fixes first — and clear about what a dehumidifier can’t fix
What’s going on in your home?
Start with the problem you can see. Every guide gives you a quick answer first, then the detail.
- Wet windows every morningWhy it happens and how to stop it for good.
Washing won’t dry indoorsDry clothes faster without the damp.
Mould keeps coming backClean it safely, then stop it returning.
A cold, damp bedroomQuiet dehumidifiers that work in cool rooms.
A steamy bathroomWhat works when there’s no socket or fan.
A damp patch on the wallCondensation, a leak or rising damp?
Free tool
What size dehumidifier do you need?
Litre ratings are measured in warm test conditions, and most UK homes are cooler than that. Our size calculator asks six quick questions — the size of your home, how warm it is, laundry, how many people and how bad the problem is — and suggests a sensible starting size and type.
- Compressor or desiccant, based on your temperature
- 10L, 12L, 20L or 25L class — with the reasons
- The features worth paying for in your situation
Drying laundry indoors
Dry washing indoors — without the condensation
A load of washing can hold a couple of litres of water after spinning, and it all goes into the air as it dries. On radiators, that ends up on your windows and walls. With a dehumidifier in a closed room, it ends up in the tank — and the clothes dry faster.
The number that matters: 40–60%
Indoor relative humidity between 40% and 60% is comfortable for people and kind to your home. Many UK homes sit at 60–70% all winter — just high enough for condensation every morning and mould by spring.
A cheap hygrometer tells you where you are in a couple of days.
Read the room-by-room guide →
Before you buy anything
Is it condensation — or something a dehumidifier can’t fix?
Condensation is one of the most common causes of damp in UK homes, and lowering humidity — often with a dehumidifier — is one of the most effective ways to deal with it. But leaks, rain getting in and rising damp need the cause repairing — a dehumidifier would only mask them.
How to tell the differenceStart here
Our most useful guides — the questions we hear most from people dealing with damp homes.
What is the ideal humidity in a house in the UK?
The humidity level to aim for in a UK home, what's too high or too low, how it changes room by room and season by season, and how to measure it properly.
The best dehumidifier for a bedroom (and how to choose one)
What makes a dehumidifier good for a bedroom — noise, size, sleep mode and type — with picks for most rooms, cold rooms and small spaces.
Desiccant vs compressor dehumidifier — which is right for your home?
How desiccant and compressor dehumidifiers work, why room temperature matters so much in UK homes, and which type to buy for each room.
How much does a dehumidifier cost to run in the UK?
What a dehumidifier costs to run per hour, day and month at the current UK price cap rate, with a calculator for your own tariff and tips to cut the bill.
9 signs you need a dehumidifier (and when you don’t)
The clear signs your home is too humid — from streaming windows to musty wardrobes — how to confirm it with a hygrometer, and when a dehumidifier isn't the answer.
Browse by topic
DehumidifiersWhich dehumidifier suits your bedroom, bathroom or flat, how compressor and desiccant models differ, and what one really costs to run in the UK.8 guides →- HumidityWhat humidity level your home should be, how to measure it, and practical ways to bring it down — room by room, season by season.2 guides →
- Mould & condensationWhy condensation forms on windows and walls, how to stop mould coming back, and when damp is a job for a landlord or a professional.3 guides →
- Buying guidesDecide whether you need a dehumidifier, a moisture absorber or something else entirely — with clear sizing guidance and what to look for.5 guides →
How we write our guides
Humidity Helper exists to help you solve the problem — which is often cheaper than buying something. Every guide starts with the cause and the free fixes, and only then covers products where they genuinely help.
When we recommend a type of dehumidifier or accessory, we explain what to look for rather than inventing star ratings or “tested” claims. Some links are Amazon affiliate links, always marked “paid link”, which help keep the site free. Read our affiliate disclosure or find out more about us.
- UK-specificSolid walls, flats, energy prices, renters’ rights and British weather.
- Cause firstWe help you fix why it’s damp, not just mop up the symptoms.
- Honest buying adviceClear about trade-offs, running costs and when not to buy.
Frequently asked questions
What humidity should my house be in the UK?
Aim for 40–60% relative humidity, ideally around 50%. Above 60% for long periods, condensation and mould become much more likely. Short spikes after showers or cooking are normal if they drop back within an hour or so.
What size dehumidifier do I need?
As a starting point, 10–12 litres for a room or 1–2 bed flat, 12–20 litres for a three-bedroom house, and 20 litres or more for serious damp or daily indoor laundry. In cold homes and outbuildings a desiccant model is usually better. Our free size calculator gives a recommendation for your home.
Will a dehumidifier stop condensation on my windows?
In most homes, yes. Running a dehumidifier in the affected room — especially bedrooms in the evening and early morning — lowers the moisture in the air so less of it condenses on cold glass. Good ventilation and wiping windows each morning help too.
Is a dehumidifier good for drying clothes indoors?
Yes. A compressor dehumidifier with a laundry mode typically dries a load in 4–8 hours in a small closed room, usually costs less per load than a vented or condenser tumble dryer, and removes the moisture that would otherwise cause condensation.
How much does it cost to run a dehumidifier?
A typical 10–12 litre compressor model uses around 150–250 watts — roughly 4–7p an hour at the October–December 2026 price cap rate of 26.32p per kWh. Using the humidity setting so it switches off when the room is dry keeps real costs lower still.
Can a dehumidifier fix damp?
It helps with damp caused by condensation — one of the most common kinds in UK homes. It cannot fix leaks, rain getting in (penetrating damp) or rising damp, which need the cause repairing. Check which you have before buying.