Should the defogging spray be applied on the inside or outside?
2 Answers
Defogging spray is a reagent used by spraying on the inside. Reasons for using defogging spray in the car: The main reason for fogging on car windows in winter is the excessive temperature difference between the inside and outside of the car. When the warm and humid air inside the car comes into contact with the colder glass, it creates fog inside the car. Therefore, the glass defogging spray needs to be applied on the inside to effectively prevent the formation of fog. Functions of defogging spray: Defogging spray not only removes fog from the glass but also forms a thin protective film on the glass to prevent the formation of fog, making it a truly effective product for ensuring driving safety. Some defogging sprays also have the function of removing dirt from the glass, making them even more practical.
Having driven for decades, I'm quite experienced in dealing with defogging issues. Defogging spray must absolutely be applied on the inside of the car windows, that is, the interior side of the glass. This is because fogging mainly occurs due to condensation from breathing and humidity inside the car on cold glass. Spraying it outside would just get blown away by the wind, potentially dirtying the exterior. In my younger days, I made the mistake of spraying it outside, wasting a whole bottle before realizing it must be applied inside.
When using it, first find a quiet place to park, thoroughly clean the glass with a damp cloth to remove dust and grease so the spray can adhere evenly. After spraying, wait a few minutes before wiping it dry with a cloth—don't rush to drive off, or the residue may blur your vision. This is especially important during winter and rainy seasons; preventive measures should be taken in advance.
I also recommend combining it with the air conditioning's defogging function for double the effect, though it consumes more fuel. Remember, clear visibility is at the core of safe driving—don't skip this small step. Make it a regular maintenance habit, and you'll avoid bigger troubles down the road.
