Why is my windshield freezing inside ?
This is a very common winter inconvenience that forces drivers to delay their departure and sometimes disrupts the start of their day: very cold temperatures, accentuated by an icy wind, cause a layer of frost to form on the outside of the windshield, which must be carefully "scraped off" with old fashioned "elbow grease" to be able to drive safely. However, frost can also appear on the inside. This phenomenon is linked to the presence of a high level of humidity in the air inside the car.
Why does frost form on the windscreen in winter ?
When the temperature falls below zero, it is quite normal for frost to form on the outside of the windshield, sometimes very thick. Inside the car, however, the rise in temperature caused by the heating and the driver's body heat triggers evaporation which, once the vehicle has been stopped and parked, is transformed into frost under the effect of the night-time cooling. This moisture is usually emitted by the driver's breathing, and increases with the number of passengers. Significant quantities of water or ice can also be introduced into the passenger compartment under shoes or on clothing that has been soaked with rain or snow.
There are fairly simple solutions to limit this phenomenon, which is generated by the large temperature differences between the outside and inside of the vehicle during the driving phase. Some of these measures are purely ""common sense"": once the car is stopped, leave a window slightly ajar to allow the humidity to evacuate and prevent it from condensing on the windshield. Be sure to shake out your jacket and shoes before entering the car, and turn off the heater when you leave.
How can I prevent the windshield from freezing inside ?
There are a number of other tips for limiting the humidity level in the passenger compartment: the use of a rubber mat is recommended because of its absorbent properties. Every textile item in the vehicle should be examined: stains or the smell of mould is a warning sign. Some drivers go even further by placing sheets of newspaper on the floor, or using kitty litter or half a potato to defog their windscreen and prevent a layer of frost from forming. It should be remembered that frost inside a vehicle can be the result of related faults, such as a malfunctioning electrical system, a blocked recirculation/filtration system or a faulty air conditioning or fan.