Damp, mould & air
Drying clothes indoors without growing mould
A freshly spun load of washing carries about two litres of water, and if it dries indoors, all of that ends up in your air. Managed well, that is fine. Here is the one-room strategy, the methods compared on running cost, and the case against the radiator habit.
By the Tickover team · Published 30 March 2026 · 4 min read
2 litres
of water in every freshly spun load
40–60%
the indoor humidity range to hold
~250W
a heated airer, about a tenth of a dryer
Where two litres goes
Water does not vanish; it relocates. Dry a load in the middle of the living room and those two litres spread through the whole house, settle on cold windows and walls, and shorten the odds on mould. Indoor drying is one of the biggest single lines in a household’s moisture budget, and the only question that matters is where you send the water.
The one-room strategy
Give the moisture a small territory and an exit. A cracked window works; in winter a dehumidifier works better, harvesting the water into a tank you pour down the sink rather than trading heat for airflow. Either way the door stays shut, and the room earns an occasional mould check behind the furniture.
The drying-room drill
- Run a second spin; flinging water out mechanically is the cheapest drying there is
- Pick one small room and shut the door
- Crack the window, or run a dehumidifier in there
- Space clothes out; a scrum in the middle stays wet for days
- Keep the airer off walls and away from curtains
- Rotate the load once, halfway through
- Wipe that room’s window next morning
What each method really uses
| Method | Typical draw | Speed | Damp risk |
|---|---|---|---|
| Vented or condenser dryer | About 2kW | Fast | Low |
| Heat-pump dryer | About 600W | Medium | Very low |
| Dehumidifier + airer | About 200W | Overnight | Low, door shut |
| Heated airer | About 250W | Slow | Medium |
| Radiator draping | Boiler pays | Slow | High, every room |
Exact pennies depend on your tariff, but the shape holds: a heated airer draws about a tenth of a conventional dryer, a dehumidifier less still, and a heat-pump tumble dryer uses modest power for far less time, so its per-load cost is competitive. The most underrated saving is that second spin: mechanically flung water costs a fraction of evaporated water.
The radiator false economy
Washing draped over radiators feels free. It is not. The boiler works harder to push heat through wet fabric, the moisture spreads through every heated room at once, and if the thermostat lives near a draped radiator it reads cold and runs the heating longer. If radiators are your only option, use one room, door shut, window cracked, exactly as above.
Indoor drying rules
Do
- Run a second spin before hanging anything
- Dry in one small room with the door shut
- Give the moisture an exit: cracked window or dehumidifier
- Space garments out so air reaches everything
Don’t
- Do not drape washing directly over radiators
- Do not dry loads in the bedroom you sleep in
- Do not park the airer against a cold outside wall
- Do not let a musty smell become the house’s new normal
Let your home run itself
Tickover keeps the whole house ticking: seasonal reminders before damp season arrives, a vault for warranties and paperwork, and your home’s running costs in one place.
Quick answers
Is drying clothes indoors bad for your health?
It is the moisture, not the washing. Two litres per load raises indoor humidity, and sustained humidity above about 60% encourages mould and dust mites, both bad news for asthma and allergies. Managed properly, in one closed room with the moisture given an exit through a window or a dehumidifier, indoor drying is fine in any home.
What is the cheapest way to dry clothes indoors?
Start with an extra spin cycle, which removes water for pennies. After that, a dehumidifier beside an ordinary airer in a small closed room is usually the cheapest powered route, with heated airers close behind. Heat-pump tumble dryers draw more power but finish hours sooner, so their cost per load stays competitive.
Why does my washing smell musty when dried indoors?
Slow drying is the cause: fabric that stays damp for a day or two grows the bacteria and mildew behind that sour smell. Speed things up with a second spin, more space between garments, moving air and a dehumidifier. If the room itself smells musty, check it for mould; the washing may be telling on the room.
Do heated airers cause condensation?
They release the same two litres an ordinary airer does, only faster and in a warmer plume, so in a closed-up room the moisture will find the windows and walls. Used in a small room with the door shut and a window cracked or a dehumidifier running, a heated airer is a tidy, cheap-to-run option.
This guide is general information for UK homes, not advice about your specific property. Anything involving gas must be done by a Gas Safe registered engineer, and notifiable electrical work by a qualified electrician. If you smell gas, call the National Gas Emergency line on 0800 111 999. If you’re ever unsure, stop and get a professional in — that’s exactly what Tickover is for.
Keep reading
Damp, mould & airFull guide
Damp and mould: diagnose it properly first
The three kinds of damp, how to tell them apart before paying for the wrong treatment, and why most cases are condensation you can fix yourself.
6 min read
Damp, mould & air
Waking up to wet windows? Fix condensation
Why your windows stream every morning, the habits and ventilation tweaks that stop it, and where a dehumidifier fits in. No moralising, no gadgets required.
3 min read
Appliances
Tumble dryer running but nothing’s drying?
A dryer that tumbles but never dries is nearly always an airflow problem: lint filter, condenser box or a kinked vent hose. Fix those before paying anyone.
4 min read