01The London flat problem
Millions of Londoners live in flats with no garden, no outside line and often no tumble dryer. Many have a washing machine squeezed into the kitchen and a folding clothes horse that comes out on wash day and stays out for two or three days. In summer, with windows open, that is manageable. In autumn and winter, when windows stay shut and the heating is on, it becomes a problem.
Wet laundry holds a lot of water, and all of that water has to go somewhere as the clothes dry. Indoors, it goes into the air of the flat. Warm air holds the moisture until it meets a cold surface, such as a window, an outside wall or the back of a wardrobe, and then it condenses into droplets. Over weeks and months, that condensation feeds black mould on window frames, in the corners of ceilings and behind furniture, and gives clothes and rooms a musty smell.
This guide explains why drying indoors causes damp, how to dry washing in a small flat with the least moisture problem, what equipment actually helps, and when it might make more sense to send laundry out. It is written for renters and owners alike, in everything from Victorian conversions to new-build blocks.
Signs drying is causing damp
- Windows running with water in the morning.
- Black spots on window frames, sills or the corners of rooms.
- A musty smell in bedrooms or cupboards.
- Clothes that smell damp even after they are dry.
- Peeling paint or wallpaper on outside walls.
02Where the water goes
When a load of washing comes out of the machine, it can still hold a surprising amount of water, even after a fast spin. As clothes dry, every drop of that water evaporates into the air of the flat.
Warm air holds more moisture
Warm air can hold more moisture than cold air. In a heated flat, the air absorbs moisture from drying clothes until it reaches a cooler surface.
Cold surfaces collect it
Windows, outside walls, the corners of rooms and spaces behind furniture are often cooler than the rest of the room. When moist air meets them, water condenses, just as it does on a cold glass.
Small flats feel it more
In a small flat, there is less air to spread the moisture through, so humidity rises faster. Modern, well-sealed new-builds can trap moisture more than draughty older flats if ventilation is not used.
03Understanding humidity
Humidity is the amount of moisture in the air. Indoors, it rises with cooking, showering, breathing and, above all, drying washing.
Measuring it
A simple hygrometer, often built into a digital thermometer, shows the relative humidity in a room. Many people find it eye-opening to watch the number climb when a clothes horse goes up.
What to aim for
Comfortable, healthy indoor air usually sits in a moderate humidity range. When humidity stays high for long periods, especially in cooler rooms, condensation and mould become more likely. If your hygrometer shows high readings most of the time, drying habits and ventilation are worth looking at.
Using the reading
- If humidity jumps when washing is drying, run a dehumidifier or open a window.
- If it stays high overnight, check ventilation and extractor fans.
- If it is high in one room only, that room may be colder or less ventilated.
04Ventilation: the first fix
Moving moist air out of the flat and drier air in is the simplest way to reduce damp from drying.
- Open a window in the room where washing is drying, even slightly.
- Keep the door of that room closed, so moisture does not spread through the flat.
- Use trickle vents on windows if you have them; keep them open.
- Run extractor fans in the kitchen and bathroom.
- Dry washing in the bathroom with the extractor fan on and the door closed, if space allows.
In winter
Opening windows in winter feels counterproductive, but a little ventilation for a few hours removes a lot of moisture without cooling the flat much, especially if the heating stays on low.
05Start with a faster spin
The less water in the clothes when they come out of the machine, the less moisture goes into the flat.
- Use the highest spin speed the fabrics allow.
- Run an extra spin on towels, jeans and heavy cottons.
- Keep lower spins for shirts and delicates that crease or stretch.
A faster spin also shortens drying time, which means less time for smells to develop.
06Clothes horses and airers
Most flat dwellers dry on a clothes horse or airer. How you use it makes a big difference.
Placement
- Put the airer in a room you can ventilate and close off.
- Keep it away from walls and furniture so air can circulate.
- Do not place it against an outside wall or under a window that already gets condensation.
Spacing
- Leave gaps between items.
- Hang shirts and dresses on hangers on the airer or a door frame.
- Lay jumpers flat on a mesh rack.
- Turn thicker items halfway through.
Heated airers
Heated airers warm the clothes gently, speeding up drying. They use less energy than a tumble dryer but still release moisture into the room, so ventilation is still needed.
07Drying on radiators
Drying clothes directly on radiators is common, but it has drawbacks.
- It pumps moisture into the room quickly, raising humidity and condensation.
- It blocks heat from warming the room, so the heating works harder.
- Clothes dry unevenly and can stiffen.
- Some fabrics can be damaged by direct heat.
- Items left on very hot radiators or near heaters can be a fire risk; keep fabric away from heaters and never cover electric heaters.
If you must use radiators, use radiator airers that hang in front of the radiator rather than draping clothes over it, and ventilate the room.
08Dehumidifiers
A dehumidifier pulls moisture out of the air and collects it in a tank. For many flat dwellers, it is the single most effective tool for drying indoors without damp.
How to use one
- Place the dehumidifier in the same room as the airer, with the door closed.
- Set it to run while washing dries.
- Empty the tank regularly.
- Some models have a laundry mode that runs harder.
Benefits
Clothes dry faster, windows stay clearer and mould is less likely to take hold. Many people find they also reduce damp smells throughout the flat.
Running costs
Dehumidifiers use electricity, though usually less than a tumble dryer. Check the running cost of the model you choose.
09Choosing a dehumidifier
If you decide to buy a dehumidifier for drying laundry, a few points help you choose.
Compressor or desiccant
Compressor dehumidifiers work well in warmer rooms and are common for homes. Desiccant dehumidifiers work better in cooler rooms, such as unheated spare rooms in winter, and give off a little warmth. Many flats suit either; if your drying room is cold, a desiccant model may perform better.
Size and capacity
Look at how much water the dehumidifier can extract in a day and how big its tank is. A bigger tank means less emptying. Some models can drain continuously into a sink through a hose.
Laundry mode
Some dehumidifiers have a laundry setting that runs at a higher fan speed while clothes dry. It is a useful feature for flats.
Noise
If the dehumidifier will run in a living room or near a bedroom, check how loud it is.
Running costs
Check the power use and estimate the cost per hour. In many cases, running a dehumidifier for a few hours costs less than running a tumble dryer, but it varies by model.
10Fans and airflow
An ordinary electric fan can speed up drying noticeably by moving air across the clothes. It does not remove moisture from the room, so it works best combined with an open window or a dehumidifier.
- Point the fan across the airer, not directly at a wall.
- Use it on a low setting; gentle, constant airflow is enough.
- Combine it with a dehumidifier in winter.
11Tumble dryers and washer-dryers
If you have space, a dryer removes the problem of moisture from drying.
| Type | How it works | Notes for flats |
|---|---|---|
| Vented dryer | Blows moist air outside through a hose | Needs a vent to the outside |
| Condenser dryer | Collects water in a tank or drains it | No vent needed; releases some warmth |
| Heat pump dryer | Recycles heat; collects water | More efficient; slower |
| Washer-dryer | Washes and dries in one machine | Saves space; dries smaller loads |
Vented dryers without a vent
A vented dryer with its hose hanging into the room releases all the moisture into the flat. Without a proper vent to outside, it makes damp worse.
Washer-dryers
Washer-dryers save space but usually dry only about half of a full wash load at a time. Split the load for drying.
12What to dry where
Not everything has to dry the same way.
- Towels and bedding: dryer if possible, or a well-ventilated airer; they hold the most water.
- Shirts: on hangers, which reduces ironing.
- Jumpers and knitwear: flat on a rack, never on a radiator.
- Jeans: hung by the waistband or folded over an airer bar.
- Delicates: flat or on hangers, away from heat.
- Sportswear: on hangers or airers; dries quickly.
13How to tell if something is truly dry
Thick parts of clothes dry last. Before putting anything away, check:
- Waistbands and pockets of jeans and trousers.
- Collars and cuffs of shirts.
- Hems and folds of towels.
- Seams of hoodies and jumpers.
- Corners and edges of sheets and duvet covers.
If any part feels cool or slightly damp, leave it a little longer. A cool feeling often means moisture is still evaporating.
14When dry clothes smell damp
If clothes smell musty even after they feel dry, they took too long to dry or were not fully dry when put away.
- Dry smaller loads at a time so each dries faster.
- Use a faster spin.
- Improve airflow with a fan or dehumidifier.
- Make sure clothes are completely dry before folding.
- Rewash anything that smells, and dry it faster.
15Putting clothes away
- Only put clothes away when completely dry, including seams and thick areas.
- Do not pack wardrobes too tightly; air needs to circulate.
- Keep wardrobes slightly away from outside walls.
- Check the back of wardrobes and drawers for mould in winter.
16The kitchen and bathroom
Kitchens and bathrooms already produce a lot of moisture from cooking and showering. Drying washing in them adds more, but they are also often the rooms with extractor fans.
Drying in the bathroom
If the bathroom has a working extractor fan and enough space, drying washing there with the fan running and the door closed keeps moisture out of the rest of the flat. Check the fan is actually pulling air: a piece of tissue held to it should be drawn in.
Drying in the kitchen
Kitchens often have the washing machine. Drying there with the cooker hood or extractor running and a window open can work, but keep laundry well away from the hob and other heat sources.
Fan maintenance
Extractor fans clog with dust and grease over time. Clean the covers and, if a fan seems weak, ask your landlord or building manager to check it.
17Avoid drying in bedrooms
Bedrooms are often the worst place to dry washing. People spend all night breathing in them, adding moisture; doors are often closed and windows shut at night; and wardrobes against outside walls are prime spots for hidden mould. Drying a load in the bedroom overnight can leave windows streaming in the morning and clothes in the wardrobe smelling musty. If you have no other choice, ventilate well and use a dehumidifier.
18Heating and drying
Keeping the flat at a steady, moderate temperature helps reduce condensation, because warmer surfaces are less likely to collect water. Heating rooms in short, intense bursts and letting them go cold in between tends to make condensation worse. If you dry washing indoors, a gentle background heat combined with a little ventilation usually works better than heating one room very hot.
19Different London homes, different problems
Victorian and Edwardian conversions
Older conversions often have solid walls, single-glazed or older double-glazed windows and draughts. Draughts help ventilation, but solid outside walls are cold and attract condensation, especially in corners and behind furniture.
Post-war blocks
Many post-war blocks have concrete construction, small kitchens and bathrooms without windows. Extractor fans may be weak or broken. Condensation on windows is common.
New-build flats
New-build flats are often well insulated and airtight, which keeps heat in but can also keep moisture in. Many have mechanical ventilation systems with vents in kitchens and bathrooms; keeping these running and their filters clean helps a great deal.
Basement and lower-ground flats
Basement flats may already be prone to damp. Drying washing indoors adds to the problem, so dehumidifiers and good ventilation are particularly important.
20Balconies and communal spaces
Balconies
Drying on a balcony moves the moisture outside, which is ideal. Check your lease or tenancy and building rules, since some buildings do not allow laundry to be hung on balconies. A low airer below the balcony rail is sometimes allowed where hanging over the rail is not.
Communal drying rooms
Some older blocks have communal drying rooms. They can be useful if they are dry and secure, but take washing back promptly.
Communal gardens
Some buildings have shared outdoor lines or space for airers. Check the building rules and be considerate of neighbours.
21Drying through the seasons
Spring and summer
Open windows, warmer air and longer days make indoor drying much easier. Balconies and open windows dry clothes quickly.
Autumn
As temperatures fall and windows close, condensation starts to appear. This is the time to start using a dehumidifier and to watch window frames for mould.
Winter
Winter is the hardest season. Air is cold and damp, heating is on and windows stay shut. Drying takes longest and condensation is worst. Smaller loads, faster spins, a dehumidifier and a little ventilation make the biggest difference.
22If mould appears
Small spots of mould on window frames and sills are a warning sign.
- Wipe small areas of mould with a suitable mould cleaner, following the instructions.
- Dry the area thoroughly afterwards.
- Find the cause: drying washing, cooking, showers, poor ventilation or a leak.
- Reduce moisture from drying with the steps in this guide.
- If mould keeps returning, covers a large area or there may be a leak, report it to your landlord or building manager.
Damp and mould can affect health, especially for people with breathing problems, allergies, young children and older people. Treat persistent mould seriously.
23Damp, mould and health
Damp and mould in homes are linked to health problems, especially breathing problems. Children, older people, people with asthma or allergies and people with weakened immune systems are more vulnerable. That is why managing moisture from drying washing is about more than tidy windows.
If anyone in the household has asthma, allergies or frequent chest infections, it is worth being especially careful: dry laundry away from bedrooms, use a dehumidifier, ventilate daily and deal with any mould quickly. If mould keeps returning despite good habits, it is important to raise it with whoever is responsible for the building and to seek advice if needed.
24Towels and bedding
Towels and bedding are the hardest things to dry in a flat. They are large, heavy and hold the most water.
- Spin them at the highest speed the label allows.
- Dry towels spread out, not folded over a bar.
- Dry sheets over two bars of the airer or over a door, folded as little as possible.
- Duvets and pillows are very hard to dry fully indoors; consider a laundry or launderette with large dryers.
25Using a launderette
Many London neighbourhoods still have launderettes with large washers and powerful dryers. They are useful for big items such as duvets and for winter weeks when nothing dries at home. Bring sorted laundry, check machines are clean and take items out promptly.
26When sending laundry out makes sense
For many Londoners in small flats, sending some or all laundry out is not a luxury but a practical answer to damp and lack of space.
- Bulky items like duvets, towels and bedding, which are hardest to dry at home.
- Busy weeks when washing piles up.
- Winter months when nothing dries properly.
- Flats where damp and mould are already a problem.
A wash and fold service collects, washes, dries fully and returns laundry folded, so nothing hangs in the flat.
27Renters and landlords
Many Londoners rent, and damp is one of the most common issues in rented homes. Both tenants and landlords play a part.
What tenants can do
- Dry washing using the steps in this guide.
- Use extractor fans and keep trickle vents open.
- Wipe condensation from windows.
- Report persistent damp, mould or broken fans promptly, in writing.
What landlords are usually expected to look after
Landlords are generally responsible for the structure of the building and for problems such as leaks, rising damp and faulty ventilation. If mould persists despite good habits, report it and keep a record. For specific rights and obligations, look at current official guidance for renters or seek advice.
28Families in flats
Families produce a lot of laundry, and young children's clothes, bedding and towels need frequent washing. In a flat, that can mean an airer up almost every day.
- Wash little and often so each load dries quickly.
- Use a dehumidifier in the drying room.
- Prioritise drying bedding and towels in the dryer or by sending them out.
- Keep children's rooms well ventilated and avoid drying washing in them.
- Watch for condensation in children's bedrooms, especially in winter.
How ArkLaundry helps
We collect from flats across London, dry everything fully and return it folded, so no washing hangs in the flat. Wash & fold is £18.50 for up to 6 kg, including VAT.
