How does condensation form?
Condensation forms when water vapour in the air inside a property comes into contact with a cold surface. It appears as water droplets or misting on surfaces such as windows, walls or tiled areas.
Water vapour can be produced as a result of normal household activities such as washing, cooking, drying clothes and burning bottled gas.
If there is excess water vapour inside a property and a lack of ventilation, insulation, or heating, then condensation can occur.
What problems can excess condensation cause?
Condensation can cause mould to grow on walls and ceilings. The first signs to look for are shiny patches on paintwork or discoloured wallpaper – mould may start to grow in these spots. Mould can appear as black spots on the walls and ceiling, increasing in size.
Mildew can also form on furniture, clothing and furnishings (this is more furry and greenish grey than mould).
Excessive condensation can affect people’s health over time. Damp and humid conditions are a breeding ground for dust mites and their droppings are allergens (allergy causing agents).
When mould grows it releases mould spores into the air which are also allergens. Inhaling these allergens can cause allergic reactions (such as sneezing, coughing, eye infections, skin rashes) and can also trigger asthma attacks in those with asthma.
Tips to avoid excess condensation
Reducing water vapour
- Try to avoid drying clothes indoors (if you must, have the window open slightly so water vapour can escape and keep the door closed).
- Keep doors closed when bathing/showering or cooking and ventilate the rooms.
- When cooking with pans keep the lids on.
- Try to avoid using bottled gas heaters.
- Ventilate your kitchen when cooking by using the cooker extractor hood or extractor fan if you have one, or open a window slightly.
- Ventilate your bathroom/shower room during and after washing by using the extractor fan if you have one, or open a window slightly.
- Keep trickle vents open in bedrooms during the night.
- Help air to circulate by keeping a small gap between larger items of furniture (wardrobes, cupboards, sofas) and the walls or floors.
- Cross ventilating can help reduce condensation that has built up overnight – if possible open a small window downstairs and a small window on the opposite side upstairs, and open the doors, to allow fresh air to circulate through the house.
- If you use a tumble dryer make sure it is vented to the outside, or use a condenser tumble dryer.
Making sure the property is warm enough
While ventilation can reduce condensation, make sure not to over-ventilate your property in cold weather – if the inside temperature drops too much it makes condensation more likely.
- Increase the temperature by putting the heating on if it is too cold (a steady temperature, rather than fluctuations, also helps combat condensation).
- If you want to heat a room that doesn’t have installed heating use an electric heater, rather than bottled gas
Other types of damp
Condensation is one type of damp, however penetrating damp and rising damp are two other common types.
Dampness could be penetrating or rising damp if the damp patches:
- have a 'tide mark' or salt deposits
- correspond with an external defect (such as a leaking roof, leaking pipe or loose guttering)
- are in areas not associated with cold spots (such as internal walls)
These types of damp would usually be your landlord’s responsibility and you should report this issue to them as soon as you notice it.