As the heating goes on each autumn, we start to get calls about streaming windows and black mould. The way a home is heated makes a real difference to condensation, and small changes can help without adding much to your energy bills.
Why condensation happens
Warm air holds more moisture than cold air. When warm, moist air touches a cold surface, such as a window, an external wall or a corner behind a wardrobe, it cools and releases moisture as water droplets. That is condensation, and where it happens regularly, mould grows.
Short bursts of heat can make it worse
Heating a cold house in short, hot bursts warms the air quickly, but the walls stay cold. Warm, moist air from cooking, showers and breathing then condenses on those cold walls. A lower, steadier temperature keeps the surfaces of the walls warmer, which reduces condensation.
Cold rooms are where mould grows
Unheated spare bedrooms, box rooms and rooms with the door kept shut often suffer most. Moist air from the rest of the house drifts in and condenses on the cold walls. Keeping some background heat in every room helps.
Practical tips
- Heat the home more evenly, rather than in short, hot bursts
- Keep doors closed when cooking and showering, and use extractor fans
- Keep trickle vents open, even in winter
- Avoid drying clothes on radiators where you can
- Leave a gap between furniture and external walls
- Bleed radiators and have your heating serviced so it works efficiently
When heating isn’t the answer
Heating helps, but it can’t solve condensation on its own if moisture can’t escape. Many homes need better ventilation, such as more effective extraction or a positive input ventilation unit. And if damp is caused by plumbing problems, rising damp or penetrating damp, heating won’t fix it at all.
Get the cause confirmed
Our surveyors measure humidity and surface temperatures to see why condensation is forming, and recommend ventilation solutions that suit your home. Learn more about our condensation and mould control service.
