What Causes Window Fog and How to Prevent It During Winter
This season we are often confronted with foggy windows and glass doors. Besides visibility problems, water leaks or window icing occurs. In order to avoid these problems, you should determine what causes window fog in your home and how you can prevent it.
Window fog is a form of condensation caused by excess humidity in your home that comes in contact with the window’s cold surface. Similarly, mirror or glass condensation is the result of taking a shower or having a cold drink in summer.
Therefore, excess humidity first shows on windows, because glass surfaces have the lowest temperature of any of the interior surfaces in the house.
What causes window fog? Temporary causes
There are three situations when temporary condensation occurs: in new or remodeled constructions, at the beginning of each heating season and when quick shifts of temperature occur. Nevertheless, if you replaced the windows for a better insulation and condensation occurs only now, it’s obvious that the house has a high humidity level. It wasn’t obvious before because some of the humidity was evacuated through the badly insulated windows.
What causes window fog? Excess humidity causes
There are many factors causing indoor increased humidity: the heating system, using a humidifier, having plants, cooking etc. One shower adds one liter of water in the air, while cooking three meals a day adds two.
What causes window fog? The ideal indoor humidity
If outdoors the temperature is down to 20 degrees, indoor humidity must be 30 – 35%, and if it’s colder, a 25% humidity must be assured. You can have it measured with a humidistat.
What causes window fog? Humidity control
You can prevent indoor excess humidity by employing a series of measures.
- A temporary solution is to ventilate the place for a few minutes when you notice window condensation.
- Open the bathroom window every time after taking a shower. Install a fan to evacuate the air.
- Use the cooker hood.
- If you grow apartment plants keep them in a brighter room and don’t excess water them in winter.
- Keep the basement as dry as possible using a proper insulation. Ventilate the attic.
- Turn to a specialist to evaluate and, if needed, improve your air evacuation system.
- Use a dehumidifier.
How to protect the windows?
PVC window frames offer a good protection against condensation, due to this material’s good insulating properties. Likewise, double glazed windows are more resistant to condensation because the interior glass will have a higher temperature. Moreover, to prevent window damage caused by condensation, you must install your radiators exactly beneath the windows. Their heat will make the water on the frames evaporate faster.
Photo credits: ibuildit.ca