The truth about drying your clothes indoors

A washing line full of fresh laundry drying in the summer sun is deeply satisfying, but what to do in the winter when it's too cold to dry your clothes outside? Here’s what drying laundry indoors could be doing to your home, and how to fix it.

Is your home way too humid?

“Indoor humidity levels should be between 40 and 60 per cent”, explains Daisy Winter, Casework Officer at the Centre for Sustainable Energy. “Drying one load of laundry in a small room of around 3m x 3m could bring the humidity up to around 96 per cent.”

For comparison, average humidity in a tropical rainforest is between 77 and 88 per cent. Predictably, raising indoor humidity levels to levels like this can cause big problems.

When this warm, humid air hits the cold glass of your window panes, it forms condensation, which can run down the glass and damage window frames. Single-glazed windows will be the most severely affected, but if the weather outside is very cold and the room isn't adequately heated, condensation and mould damage can also build up on double-glazed windows.

In addition to window frames, high humidity can also cause mould to form on walls, ceilings and even furniture. While this is bad for your decor, it’s even worse for your health. Research conducted by the UK Health Security Agency found exposure to damp and/or mould was associated with approximately 5,000 new cases of asthma and approximately 8,500 lower respiratory infections among children and adults in English housing in 2019.

BUT, it does keep your house plants happy!

While you might be struggling with the damp, your house plants will probably be basking in it. Many indoor plants prefer a bit of humidity, which is why they thrive in a room with a high moisture level, such as a warm, steamy bathroom, but struggle in hot, dry zones such as above a radiator or fireplace. The water released by your washing probably won’t bother them at all.

However, many house plants really hate a cold draft, so if your plants are in the same room as damp laundry, ensure they’re sheltered from any cold air flowing in from open windows and ventilation points.

Mould damage can also potentially affect the value of your home if left untreated. According to the 2025 UK Houzz & Home Renovation Trends Study, deterioration and damage due to home age and issues such as mould are key drivers of home renovations. Almost one in five homeowners admitted to using up their home renovation budget to address these issues and maintain the value of their home.

6 ways to beat mould in your home

1: Use an extra spin cycle

“Drying clothes inside can produce almost two litres of water”, Daisy says. To wring as much water out of your clothes as possible before hanging them up indoors, try using a second spin cycle on your washing machine. This can help to cut down drying time and reduce humidity.

2: Assign a drying room

Draping damp washing around multiple rooms will increase humidity right through your home. Instead, hang your washing in a single room with the internal door closed and a window open. The best rooms for this are ones that are naturally warm and easily ventilated. Avoid naturally damp, cold environments such as garages or basements.

3: Use an extractor fan

Using a room with an extractor fan, such as a bathroom, for drying laundry is ideal. “It'll pull the moisture from the air but won't feel quite as cold as having the window open” Daisy says. “You want to keep the room warm enough that condensation doesn't form on cold surfaces such as windows and uninsulated walls.” Opening trickle vents around windows can also help ventilate a room when it’s too cold to fully open a window.

4: Don’t drape clothes over radiators

Although it might be tempting to place clothes directly on radiators to speed up the drying process, placing anything on top of a radiator can stop warm air from circulating properly around the room, increasing humidity levels. Hang them on a clothes airer instead, or try a heated drying rack.

5: Get a hygrometer

Prevention is better than cure, so Daisy suggests using a humidity monitor called a hygrometer to help track the amount of moisture in the air. This can help you to spot when levels creep too high, so that you can take action quickly.

6: Consider a dehumidifier

If you’re still struggling with damp and mould indoors, a dehumidifier can help to regulate indoor moisture levels. Daisy recommends setting it at under 60 per cent humidity and closing doors and windows when it’s running. “Mould can't grow at less than 60 per cent humidity, which is why it is so important to keep the humidity levels down in your home,” she says.