Window condensation: causes and solutions
10 June 2026 · 4 min read
Why condensation appears on glass and how to get rid of it: humidity, temperature and correct ventilation in winter.
Condensation on the inside of the glass does not necessarily mean a faulty window – most often it is a sign of too much humidity in the house. Here are the causes and what you can do.
Why condensation appears
Warm indoor air holds water vapour (from cooking, showering, breathing, plants). When it touches the cold glass surface, it turns into droplets. The higher the indoor humidity and the lower the temperature, the more condensation forms.
Simple solutions
- Ventilate briefly and intensely: 10–15 minutes, 2–3 times a day
- Keep the indoor temperature between 18 and 21°C
- Keep humidity below ~50% (a cheap hygrometer helps)
- Do not block the radiator under the window
- Use the window's tilt (partial ventilation) function
Frequently asked questions
Does condensation damage the windows?
Over time, constant humidity can affect seals and sills. Fixing ventilation prevents the problem.
Does triple glazing eliminate condensation?
It greatly reduces the risk because the inner glass surface stays warmer, but correct ventilation is still essential.
