What is it? Where does it come from? Where does it go?
Condensation happens when moist air comes into contact with a cool surface and creates water droplets. On your window, the glass mists up and drops of water run down the window. When it happens on a wall, the wall soaks up the moisture and becomes damp. Mould could then grow on the damp areas.
Your body produces moisture all the time, when you breathe or sweat. This is more noticeable when you exercise and overheat. We also put lots of moisture into the air when we take a bath or shower, cook or wash the dishes. Moisture is also produced when we dry clothes indoors or use a tumble dryer or even when ironing clothes.
Years ago our buildings had natural ventilation through chimneys, for example. There were often draughts at doors and windows. We now have homes that are sealed and draught proofed – so we need to do something to let the moisture out.
If you dry close indoors think about the amount of moisture that will be created in the air. Where will it go? You need to open windows and heat your home. Otherwise the moist air will find the coldest surface and turn into ('condense') to liquid. This causes mould if you don't clean it regulary. This short video shows how much water is created by drying a few towels.
Where can it happen?
Condensation happens most on the cool parts of walls, particularly on outside walls where there’s not much air movement. It can appear as a dark patch in corners near the skirting and on the ceiling. The side walls of windows are often affected as they can be even colder. Areas with poor ventilation will get condensation. This could be behind furniture, particularly wardrobes and beds if they have been placed against an outside wall. Bedrooms are often at risk because they are cooler. Double glazed windows are unlikely to have surface condensation except temporarily in kitchens and bathrooms. If condensation is on your window where the glass meets the window frame you must wipe it off and dry the surrounding area as quickly as possible or it will cause the timber and seals to rot.
Moisture is also found in bathrooms and is easily seen on tiles. To prevent mould, open the window after bathing or showering and wipe the tiles down. Each time you flush the cistern it fills with cold water and will attract moisture which will condense on the cistern and on the wall behind. Make sure you dry and clean this to prevent mould.
How to remove mould
Mould can be easily removed. Wipe it off with a disposable cloth, using some household cleaner. There’s no need to use strong chemicals. Wipe over the area again every few days using diluted household cleaner to stop the mould growing back. This should become part of your regular cleaning routine.
To reduce the risk of condensation in your home:
Keep a window open when drying clothes indoors
Don’t dry clothes over warm radiators
Keep the kitchen door closed when cooking
Keep lids on pots and pans when cooking
Keep the bathroom door closed when running a bath and bathing
Open the bathroom window to let the moisture out
Don’t overfill cupboards and wardrobes - let air circulate
Use the extractor fan in the kitchen and bathroom
Don’t put furniture or beds hard against walls – let air circulate
Keep your heating on low throughout the day in cold weather
Set your central heating time clock to heat your home at least part of the day. Your house can be warm for you getting up in the morning or coming home from work
Don’t use gas or paraffin heaters
Properly heat and ventilate rooms at risk
Put the tumble dryer hose out the window or door
Keep your home warm:
Don’t trap heat – don’t put furniture in front of a radiator
Keep curtains above radiators
Thick curtains stop heat escaping – close them at dusk
Keep curtains open on sunny days to help warm rooms
Keep doors open in sunny rooms to let warm air to circulate
What to do next
If you find condensation and problems with mould follow the advice in this leaflet or contact us. We will visit to discuss this with you.