Fogging of windows in a car is a common phenomenon that a car owner can observe at almost any time of the year.. Why does this happen and what to do about it.
In a working car, the heating and ventilation system copes with fogging within one to two minutes. If this does not happen, this, in addition to natural reasons, may indicate a problem.
The effect of glass fogging in a car occurs due to condensation – a physical phenomenon observed when there is a significant difference in air temperature with the surface of the glass and high humidity.
Many passengers in the cabin
A large number of people in a confined space immediately provokes fogging of the windows.. The greater the volume of exhaled air, the more actively water condenses.. And if it’s raining or foggy outside, the process speeds up literally significantly.
High concentration of moisture inside the car
For example, if there are a lot of wet things in the cabin, or the passengers themselves are sitting in wet clothes. Also the cause may be pile rugs that are saturated with a large amount of water.. The fumes from them will also appear in the form of fogged windows.
Clogged cabin ventilation filter
One of the most common causes of car windows fogging up.. It is noteworthy in that it can occur without other typical factors affecting window fogging, such as wet weather, large temperature differences between inside and outside, or high humidity in the cabin.
An old cabin filter, which has not been changed for a long time, accumulates not only microparticles of dirt from the air, but also moisture. Air flows from the ventilation system, passing through a clogged filter, also cause moisture to settle on the glass.
Recirculation damper malfunction
In any automobile heating and ventilation system there is a damper responsible for switching the air supply to the cabin. In one position it takes in the flow of fresh air from the street, in the second it takes it into the cabin, providing a closed cycle.
Often this valve gets stuck in the closed position.. Thus, the air will constantly circulate inside the cabin, gradually filling with moisture from the breath of the driver and passengers.
Very high humidity outside
If it is raining outside, there is heavy fog, or simply high humidity, this also contributes to fogging of the windows in the car. Here the effect will be similar to a recirculation damper stuck in the closed position. The only difference is that even air supplied from the street will be saturated with moisture, causing fogging.
Coolant leak
Often, even a minor malfunction of the cooling system, such as leakage of antifreeze, is the culprit of fogging. A distinctive feature of this reason is a thin translucent sediment remaining after the moisture evaporates from the glass. There will also be a characteristic sweetish smell in the cabin.