For a properly functioning auto, what's the quickest way to defog the windshield? There are lots of air control options - hot vs. cold air, exterior vs. recirculated air - but which are the most effective (assuming the auto is functioning correctly)?
It will depend on your car, the outdoors humidity, the air temperature and the engine temperature. As an example, for me on a cold icy morning starting with a cold engine:
- aircon on
- fan on low
- use external air, not recirculator!
- front windscreen demister (covers wiper rest area)
- rev engine until at working temp
- then put fan on high
But in high humidity areas in the summer I would use:
- aircon on
- fan on high
- use recirculator
Hot air from the exterior with your a/c on is the quickest. Though in general having the a/c on is the most important piece, as it removes moisture from the air.
My old Fiat Marea Weekend had instructions for defogging the windshield on the inside of the driver's visor:
- Turn the blower on max
- Turn the heat on max
- Turn the recirculation off
- Put down the visors
I was wondering about that last bit, so I've asked a follow-up: