Moisture is always present in the air, even if it's invisible. Condensation occurs when this warm, moist air hits cold surfaces such as windows, floors, or walls.
You can see condensation when your breath fogs up in cold weather or when a mirror steams up during a shower or bath.
Condensation can cause mould over time, which looks like small black dots and smells musty.
There is always some moisture in the air, even if you can’t see it. Condensation forms when warm moisture in the air comes into contact with cold surfaces like windows, floors or walls.
You notice it when you see your breath on a cold day or as the mirror mists over when you have a shower or bath.
Over time, condensation can lead to the growth of mould. Mould appears as a cloud of little black dots and has an unpleasant musty smell.
The causes of condensation are:
- too much moisture in the air
- poor ventilation
- your home is cold
There are some simple steps you may be able to take to reduce condensation.
Stop moisture building up
Everyday activities like drying clothes, cooking, taking a shower and even breathing create moisture. To stop moisture building up, you can:
- always wipe down surfaces where moisture settles
- dry laundry outdoors if you have outside space
- avoid drying laundry directly on radiators
- dry laundry in the bathroom with the door closed and the window open or extractor fan on
- if you have a tumble dryer and it is not self-condensing, vent it outside
- cover boiling pans when you’re cooking
- turn down heat on boiling pans to a simmer
- avoid using portable heaters if possible
- keep your kitchen and bathroom doors closed when using these rooms as this will help prevent the spread of moisture
- use extractor fans in your kitchen and bathroom, if you have them
- run the cold water first if you’re having a bath
Improve ventilation
As well as on cold surfaces, condensation appears in places where there is little air movement – for example, in corners and in or behind wardrobes and cupboards.
It is important to keep air circulating in your home to reduce condensation.
Ventilation removes moisture and stale air from your home and replaces it with fresh dry air.
To improve ventilation, you should open windows or vents regularly during dry weather. It is better to open a few windows a little throughout your home rather than have one window wide open.
Doing this regularly for short periods is the best way of ventilating your home and will minimise heat loss. Keeping windows and vents closed to stop heat getting out will not help reduce condensation.
Other steps you can take are:
- if you have background or trickle ventilators, keep these open all the time
- open the window slightly or turn on the extractor fan when using your kitchen or bathroom
- avoid overfilling cupboards and wardrobes as this stops air circulation
- where possible, position wardrobes and furniture against internal walls
- leave space between furniture and the wall
- do not block air vents
Keep your home warm (if you can)
A cold home is more likely to be a damp home.
Condensation forms more quickly when your home is cold because cold air can hold less moisture than warm air.
We know that many people are struggling with difficult choices between heating and eating because of the cost of living crisis. If you can afford to, the recommended room temperature for heating your home is 18 degrees.
If you are older, have children under five or have a health condition putting you at risk from cold, the recommended room temperature is 21 degrees.
Keeping a low background heat on all day is more effective than short bursts of high heat.
Avoid the use of portable heaters if you can as they produce very high levels of condensation.
Your home may be cold for other reasons like poor insulation. These pages also give details of support that may be available to improve conditions - including energy efficiency - in your home.
