How to Defog Your Windshield Twice as Fast: What the Science Says, by CarGuru Tech on YouTube. 4 min 49 s.
- Video length
- 4 min 49 s
- Time to do it
- 5 minutes
- Difficulty
- Easy
- Steps
- 8
What you need
Steps
Start the engine and press the front defrost button, the one with the windshield symbol. This aims airflow at the glass where the fog sits.
Turn off the air recirculation button so fresh outside air comes in. Recirculation keeps the damp cabin air inside and the fog stays.
Switch on the AC compressor, even if you want heat. The AC dries the air as it passes through, which is what actually clears the glass.
Set the temperature to warm and the fan to medium or high. Warm dry air holds more moisture and pulls it off the glass faster than cold air.
Point the side vents at the front side windows and press the rear defroster button if the back glass is fogged too.
Crack one window open for the first minute. This lets the humid air escape instead of circling back onto the glass.
Lower the fan once the glass is clear, but leave the AC on and keep the vents on the windshield. This stops the fog from creeping back.
Wipe the inside of the glass with a microfiber cloth and glass cleaner when you park. A greasy film makes fog form sooner and hold on longer.
Tips and common mistakes
Never wipe the windshield with your hand or sleeve while driving, since it smears and blocks your view. Pull over first.
If your windows fog up constantly, check the cabin air filter and look for damp mats or leaks that keep moisture inside the car.
Shake out wet umbrellas and knock snow off your boots before getting in, as carried-in moisture is a common cause of repeat fogging.
Do not pour hot water on a fogged or frosted windshield in cold weather, as the sudden temperature change can crack the glass.
Questions
Should I use hot or cold air to defog the windshield?
Warm air works better once the engine is warm because it holds more moisture, but it clears slowly at first. Cold AC air with the compressor on clears glass fast in humid rain and is fine for a quick fix.
Why does the fog come back right after I clear it?
Moisture is still in the cabin, usually from wet clothes, mats or breathing passengers. Keep the AC on with fresh air coming in and crack a window until the inside dries out.
Does the recirculation button really make fog worse?
Yes, in most cases. It traps the humid air already inside the car and sends it back to the glass, so the fog returns. Use fresh air mode while defogging.
This guide was drafted from the video's details and general task knowledge. It has not been checked against the full video. Check the video and relevant product instructions before following a procedure. Report a correction.
