What to do when plastic windows sweat. The reasons. How to deal with fogging windows

What to do when plastic windows sweat. The reasons. How to deal with fogging windows Many owners of pvc windows observe a not very pleasant phenomenon, such as sweating of pvc windows.

This can be accompanied by mold growth.

It is believed that this has nothing to do with the quality of the insulating glass units themselves, but most likely with improper installation and operation. We will try to figure out - when plastic windows sweat - what to do.

Why do plastic windows sweat from the inside and what to do about it?


Changes in the microclimate from inside the room ..

. There is a need for more frequent ventilation. Wooden frames with slots facilitate natural gas exchange. All the moisture and carbon dioxide exhaled by household members during cooking, etc., cannot be completely removed by the ventilation system.

When installing plastic double-glazed windows, the penetration of air into the apartment is reduced tenfold, which naturally increases the concentration of carbon dioxide and humidity.

Change of external microclimate. More often condensation occurs due to the contrast of temperatures - outside and inside the house.

What to do when plastic windows sweat. The reasons.</p><p> How to deal with fogging windows Another temperature factor is the location of the house relative to the cardinal points. The northern windows are naturally colder than the southern ones and the moisture on them will take longer to evaporate.

It all looks like this: at first, fogging looks like multiple drops of water on the glass, which flow down to the windowsill, forming puddles.

This water freezes when the air temperature outside the window drops. The same thing begins to happen along the slopes and corners of the frames, as a result of which fungal growths are formed.

Note : The appearance of condensation occurs due to the fact that the glass unit has a low temperature inside.

The reasons why the glass surface is cold can be identified:

  • A glass unit has a low thermal insulation index;

Note: Economists need to understand that single-chamber double-glazed windows with ordinary glass cannot be used for a living room.

A very large window sill, which limits the passage of air from the radiator to the window opening;

  • Errors in the manufacture and installation of the window.

    Such as, the geometry of the sashes was violated, the clamps were not adjusted, the assembly seam was not of high quality foamed. All of these can lead to window sweating on handles, hinges and corners.

An increase in humidity inside the room occurs due to a violation of air exchange. Previously, window frames were made of wood and did not have a dense structure, so air exchange was carried out naturally. Modern pvc windows are less breathable.

They have from two to three sealing circuits, so air does not penetrate from the street, the hood begins to malfunction, as a result - disrupted air exchange and moisture accumulation.

It is impossible not to mention the type of glass units themselves.Two-chamber and three-chamber, especially in cold regions, will be much more effective than a single-chamber type .

How to fight

First, you need to ensure. for ventilation to work properly.

If this is not the case, then you need to periodically arrange ventilation.

Note : Forced ventilation is an effective tool.

To avoid condensation on the windows, you do not need to save on their purchase. It is better to immediately choose windows of a warm configuration with two chamber double-glazed windows and energy-saving glass.

When installing wide window sills, take care of the ventilation grill so that warm air from the radiator reaches the window.

Also, make sure that all seams are thoroughly foamed when installing windows.

What to do when plastic windows sweat. The reasons. How to deal with fogging windows If the condensate is caused by installation defects or insufficient equipment, then it can be eliminated only by eliminating these shortcomings.

Note: If there is sufficient air flow from the street to the inside, no condensation will appear even on sealed plastic insulating glass units.

When detecting the cause, it is mandatory to check the operation of the exhaust ventilation system.

When you have determined that the hood is working properly, all that remains is to provide fresh air.

Fresh air can be provided artificially in several ways:

  • By ventilation;
  • Ventilation using an independent window valve;
  • The last method is to create a window with a breathable profile.

    This is the latest technology thanks to which the room will be supplied with fresh air in any weather. This option is much more convenient than daily ventilation and is cheaper than installing valves.

If the windows are not new, then to detect a problem, the sealing gum should be checked and, if necessary, replaced. As mentioned earlier, the edge zone of the windows is the coldest place. Adjust fittings, as seals can lose their elasticity over time.

In any case, all actions taken should be aimed at reducing the humidity in your home.


It is better to prevent fogging of windows than to try to get rid of it later. You should start at the stage of acquiring windows. You can't skimp on quality. After all, this is very important for creating a favorable microclimate for the home.

Ignoring these points can even lead to the repeated replacement of the glass unit.