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Frost inside windshield?

Discussion in 'Gen II Prius Main Forum' started by clongwor, Dec 30, 2007.

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  1. clongwor

    clongwor New Member

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    I don't remember noticing the last 2 winters, but this year whenever it gets frosty outside, there is also frost inside the windshield. This morning I had to scrape inside the car.

    Is this normal? There seems to always be a lot of fog in there too.
  2. davidtm

    davidtm New Member

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    I would recommend turning AC "on" in the Climate screen, as that will de-humidify the air inside the car, even when you're not running the defrost mode. Then, there won't be the moisture inside that will condense or freeze on the inside surface of the windows. The AC compressor will not run if the outside temp is too cold, so the hit on mpg won't be so bad.
  3. seasalsa

    seasalsa Active Member

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    It is normal if you have AC off. Hit the Auto/AC button on your wheel and it will take care of the frost as stated above.
  4. john1701a

    john1701a Prius Guru

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    Using RECIRCULATE allows for moisture build up.

    I never do in the during the cold season and have yet to ever see frost inside... here in Minnesota driving a Prius for 8 winters now.
    .
  5. clongwor

    clongwor New Member

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    Thanks everyone!

    That's exactly the problem. I started shutting off the A/C and also started choosing RECIRCULATE in the mistaken belief that it would warm up the car faster than bringing air from the outside.

    Duh!
  6. TonyPSchaefer

    TonyPSchaefer Your Friendly Moderator Staff Member

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    Well don't come down on yourself too much. The recirculate for warmer air was a good idea and you're right. Unfortunately, you simply failed to take into consideration the water vapor in your breath that is also recirculated.

    Live and learn and pass it on.
    Trust me, many of the tips most of us pass on were learned the hard way.
  7. jsuh84

    jsuh84 New Member

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    It was freezing here in Chicago today and I had the same problem. What bothered me was that I just got my '08 Prius this past weekend, and already I couldn't believe a problem like this would occur.

    I'll be following the suggestions. Thanks.
  8. smithBYU85

    smithBYU85 New Member

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    I'm in Utah and I have the same problem. I started turning the A/C on to stop it. My problem is that I normally leave the heater off when I'm by myself to help out with my MPG, with a coat and gloves on I stay pretty comfortable.
  9. David Beale

    David Beale Senior Member

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    First, put the climate control system in "auto" mode.
    Then just go to the climate screen (press "climate") and select front defrost on the bottom of the screen buttons.

    Presto, the windshield is cleared in just 10-20 sec. If you leave it on it's a little noisy, but the windows will not fog up.
  10. qbee42

    qbee42 My other car is a boat

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    Just to add to the above posts, the climate control system on the Prius is fairly smart, and the A/C compressor is unlike that in most cars. The Prius will only run the compressor when it needs to, even when it is switched on, and the compressor is driven by a variable speed electric motor: If the climate control needs just a little bit of cooling or drying, it will run the compressor at a low power setting. It's not like the all-or-nothing clutch controlled compressors on normal cars.

    Tom
    1 person likes this.
  11. Stringmike

    Stringmike New Member

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    Move further south.

    Mike

    Scottsdale, Arizona
  12. billarb

    billarb New Member

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    I'm a new owner (~3 weeks) and noticed condensation on the inside of the windshield tonight coming home from work. I'm glad I read this string, because I now know to shut off the recirculate. All that said, I like Mike's solution better!!!
  13. orracle

    orracle Whaddaya mean "senior" member?

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    Boy am I glad I found this thread! This morning at zero or near abouts, after I pulled out of the garage the inside frosted over so badly I had to scrape! I tried about everything including the previously mentioned wrong things to do. I just didn't believe the a/c button would take care of things.
  14. jayman

    jayman Senior Member

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    As others have mentioned, it's really important to take all excess snow off your boots. The Prius uses partial recirc to save energy, not the best thing in bitter cold temps.

    Also make sure the air intake vents are clear. When the cabin fan is turned on, it can suck in snow
  15. PrematurelyGray

    PrematurelyGray New Member

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    Jayman brings up a good point - you might have excess moisture (like snow on boots) that won't dissipate in these temps. My son spilled a bottle of water on the floor in December and didn't tell me. Still suffering from excess moisture and waiting for some 60 degree days to dry the car out.
  16. NoMoShocks

    NoMoShocks Electrical Engineer

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    Really! Has living in Scottsdale helped you to use your AC less all year long? Seriously though, I know it is a nice place.

    I found the suggestion to clear the intake vents good. I assume they are at the back of the hood just in front of the windshield wipers, so I will be doing that next time I get snow.
  17. donee

    donee New Member

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    Well, that is an understatement. I put my car to bed wet from the warm damp drive home (40 F), only to wake it up in the morning at -2 F. And in the mean time there were winds gusting to 40 mph, and snow blowing into little tiny (6 inch) drifts, with bare pavement inbetween.

    There was also ice under snow where the snow melt water had not drained before the thermal shock hit. So, the traction control got a good workout. But I never got stuck.

    I had about 1/4 th of the inside of my windshield frosted, and all of the rear hatch window. I remember my Saturn SL2 frosting over the inside of the windshield on occaision, but not the rear window. I think they need to double up of the heater wires in the hatch window.

    It was sunny today, and its all gone now.
  18. dustyhuskie

    dustyhuskie Itchy Tomato

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    Are there wires in the bottom hatch windows? I though maybe not as the window ice seems to melt very slowly if at all.

    I keep a scraper in the passenger seat. I get in the car with wet hair. Par for the course. First time it happened I didn't have a scraper and had to keep scratching patchs off the window to see the road.

    Detailing with steam cleaning the carpets/seats seems like it may be out of the question.

    With auto on the air will come on automatically in response to just humidity? I noticed that it was on even with the interior of the car was freezing and thought it was just another charming Prius glitch.
  19. diamondlarry

    diamondlarry EPA MPG #'s killer

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    I have had my windshield completely frosted over a few times this winter; had to use my ice scraper on the inside. I drive with the driver's window and the right rear passenger window cracked open about 1". I would think that any moisture from my breath would be sucked out of the car with the windows open.:confused: This is the first car I've ever owned that I've had this happen.:confused:
  20. richard schumacher

    richard schumacher shortbus driver

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    With recirc on, the wet air from your boots doesn't get sucked out fast enough; it blows over the windshield first and the water condenses there. Consider it a testament to the air-tightness of the cabin. Turn on the defrost, make sure it's set to outside air and all should be well (except for sucking in exhaust from other vehicles...).
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