Drying Clothes Indoors Without Mould: A Practical Guide

Short answer: pick one room, close its door, and get the moisture out of that room while the washing dries: a window open a little, an extractor fan running or a dehumidifier on. Don't spread washing on radiators around the house, and never dry it in bedrooms. Research from the Glasgow School of Art found an average load releases around two litres of water into the air as it dries. In a cold, closed-up house in winter, that water has to go somewhere, and it usually ends up on the coldest walls and windows.

How much moisture are we talking about?

The best-known UK study on this was carried out by the Mackintosh Environmental Architecture Research Unit at the Glasgow School of Art, with Strathclyde and Glasgow Caledonian universities. Looking at 100 homes in Glasgow, the researchers found:

87% of households dried washing indoors in colder weather
an average load released around two litres of moisture while drying
drying laundry on airers by radiators in poorly ventilated rooms could account for up to a third of the moisture in the home
most homes had no suitable space set aside for drying clothes

Two litres is roughly a large bottle of water, per load, emptied into the air. Do three or four loads a week and it is easy to see why windows stream in the morning and black mould appears in corners.

Why radiators make it worse

Draping washing over radiators feels efficient, but it:

pumps moisture into the warmest air, which then drifts to colder rooms and condenses there
blocks the radiator's heat from the room, so walls stay colder
makes the boiler work harder to dry clothes rather than heat the house

A clothes airer near (not on) a radiator, in a room you can ventilate, is a better option.

The best way to dry clothes indoors

Spin them hard first. Use the highest spin speed the fabric allows. Every bit of water left in the drum is water that has to evaporate into your home.
Choose one room and use it every time, ideally a bathroom, utility room or kitchen with an extractor fan.
Close the door so moist air doesn't spread to colder rooms.
Ventilate that room: run the extractor fan, open a window slightly, or both. Opening a window just a crack for the whole drying time beats opening it wide for five minutes.
Or use a dehumidifier in the same closed room. Many models have a laundry mode, and clothes often dry faster than on an airer alone. See do dehumidifiers stop mould? for running costs.
Don't overload airers. Space between items lets air circulate and things dry quicker.
Keep it out of bedrooms. You'd be adding laundry moisture to the moisture people breathe out overnight, in the room that's often coldest. Our post on sleeping in a room with mould explains the health side.

Tumble dryers: which kind?

Vented dryers blow hot, wet air out through a hose. That hose must go outside through a wall or window vent. A vented dryer with its hose dangling into the room is one of the worst things you can do for condensation.
Condenser dryers collect water in a tank or send it to a drain. They still release some warmth and moisture, so run them in a ventilated room.
Heat pump dryers are condenser dryers that use much less energy. Higher upfront cost, lower running cost.

Building regulations guidance for new work expects a utility room to have an extract fan of 30 litres per second, which shows how much moisture a laundry space is expected to produce.

Outdoors when you can

Even in winter, a dry, breezy day will get a lot of water out of a load before you bring it in to finish. A covered outdoor line, a porch or a garage with ventilation all help.

Signs your home can't cope

Windows streaming with condensation most mornings
Black spots in corners, behind furniture or around window frames
A musty smell that doesn't go away
Clothes that take more than a day to dry indoors

If you're seeing these even after changing how you dry washing, the problem is likely to be ventilation, heating or insulation, or a damp problem that isn't condensation at all. Our condensation causes page explains the main culprits.

For landlords and tenants

Drying clothes is a normal part of living in a home. Government guidance on damp and mould says it is unreasonable to blame damp and mould on tenants' "lifestyle choices", and recommends that landlords think about where tenants can dry washing, ideally outdoors in a secure, covered space.

In practice that means:

Landlords: make sure the bathroom and kitchen have working extract fans that meet current guidance, check trickle vents are fitted and clear, provide somewhere to vent a tumble dryer, and consider a covered outdoor drying area. Our guide can a landlord blame condensation on tenant lifestyle? sets out where the line sits.
Tenants: use the steps above, report mould in writing with photos, and mention any broken fans or vents.

FAQs

Is it bad to dry clothes on radiators?

It adds a lot of moisture to the air and stops the radiator heating the room properly. An airer in a closed, ventilated room is better.

Does drying clothes indoors cause black mould?

It can contribute, especially in cold, poorly ventilated homes. Laundry moisture condenses on cold walls and windows, which is where condensation mould grows.

Is it cheaper to use a dehumidifier or a tumble dryer?

It depends on the machines and your tariff. A compressor dehumidifier often uses less electricity than a vented or condenser dryer, though clothes take longer. Heat pump dryers are the most efficient dryers.

Which room is best for drying clothes indoors?

A room with an extractor fan and a door you can close, such as a bathroom or utility room. Avoid bedrooms and living rooms.

How to dry clothes indoors without causing condensation and mould