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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)?

SQB
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KatieK
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3 Answers3

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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
Rory Alsop
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4

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.

Scott Hillson
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1

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:

Does putting down the visors help defogging the windshield?

SQB
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