Windows constantly fogging up

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Temperature is creeping below 0°c and I have a problem where my windows are fogging up, at worst, every 2 minutes. I blast max to make it go away, but it comes back pretty quick if I turn off max. I've tried different auto settings with and without ac. I've tried turning off auto and use the settings for window shield heat etc. I haven't found anything that works. Was told there might be a future update for it. But it's pretty annoying driving the car long distances having to blast max fans frequently to be able to see out. The fog starts in the back and creeps forward. Sometimes I can feel the air suddenly become very humid, but it quickly goes away when fans are going at max.

Anyone else have this problem? Did you find a solution for it?

(2022 GT)

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[AKgrampy]

I just find I have to switch to defrost (not max defrost ) when things begin to fog up. I have found here in Alaska that I can not run in Auto mode. It will always fog up and it is almost instantaneous. So I run with a fan speed of 4, temp of 68 (sometimes 70), and floor + defrost selected in climate. When it starts to fog I just eliminate floor for awhile. Sometimes forget to switch back but cabin remains comfortable enough. I have noticed lately that I can tell when the heating system is robbing heat for the battery and has less for the cabin. That may be just my imagination though. I have not driven below -20F as I choose to drive my ICE vehicle in those conditions. Just another frigid 22 Ruby Red GT owner sharing their experience. My GT also has a hard top which helps a lot.

 

[Mrn]

If AK's method doesn't do it, you might also try opening a left and right window just a bit to get some of the moist air out of the car.

 

[AKgrampy]

If AK's method doesn't do it, you might also try opening a left and right window just a bit to get some of the moist air out of the car.

I have tried that too! Problem I find is we have snow on the ground from Oct to April so the driver mat is almost always wet so moisture never goes away.

 

[Mach-Lee]

With the latest HVAC update for fogging, it does a decent job. Below 0ºC I sometimes get a tiny bit of fogging, but it goes away after a minute or two automatically (most of the time I don't have to do anything). In rare cases where it doesn't go away on its own, then I switch to defrost for a minute to clear it up, then switch back to AUTO.

Having puddles of melted snow on the mats is going to make things extra difficult, so you might have to run it defrost mode manually with an elevated blower speed. Try to minimize the amount of moisture in the cabin if possible.

If you run defrost a lot, it's going to cause a range hit since more heat is wasted in defrost. A little fogging is a good sign you're saving as much heat as possible.

 

[MacherAWD]

I have tried that too! Problem I find is we have snow on the ground from Oct to April so the driver mat is almost always wet so moisture never goes away.

I have the all rubber mats, I wonder if that helps with moisture. I also am up to date on all OTAs, well 6.7. but today, lots of driving 20-30F kids in the car, Auto, speed 1, 68 no fog, we recently came back in 30F rain/snow, 4 people for 2 straight hrs, same climate setting, no fog. I do notice that climate set like that if ac turned off it fogs quickly so sometimes I turn that back on with auto.

 

[Mach-Lee]

If you could wipe up the water on the floor mats with a towel and put it in a sealed plastic bag that would help.

 

[AliRafiee]

Make sure A/C is on and you are on fresh air.
A/C is important because it drys the air.

 

[Mach-Lee]

Make sure A/C is on and you are on fresh air.
A/C is important because it drys the air.

A/C won't work below freezing. Fresh air is the only way to drop the humidity when it's freezing.

 

[AliRafiee]

A/C won't work below freezing. Fresh air is the only way to drop the humidity when it's freezing.

Why doesn’t it work?

 

[Mach1E]

Why doesn’t it work?

Because it works moving heat (moves heat from inside your car to the outside).

But if it’s freezing, there isn’t any heat to move.

Condensation forms from the temp differential which is how it dehumidifies (that’s the water dripping under your car when the ac is running).

This is one of the downsides of not having a heat pump. The heat pump would dehumidify when running in the winter.

 

[AliRafiee]

Because it works moving heat (moves heat from inside your car to the outside).

But if it’s freezing, there isn’t any heat to move.

Condensation forms from the temp differential which is how it dehumidifies (that’s the water dripping under your car when the ac is running).

This is one of the downsides of not having a heat pump. The heat pump would dehumidify when running in the winter.

It’s not about heat exchange. It’s about drying the air. EDIT: I just noticed you said that doesn’t happen either.
Anyway, works for me.

Take a pick of any of these sites.
https://www.google.com/search?q=defog+inside+car+windshield

 

[Mach-Lee]

Why doesn’t it work?

Short answer: A/C just doesn't work below freezing because it's too cold.

Long answer: The cold will affect the pressures and temperatures of the system, causing problems with refrigerant evaporation and potential flood back, which can damage the compressor. Due to low head pressure, the pressure delta across the expansion valve is too low for stable feeding to occur, which can cause excessive swings in superheat. The evaporator could easily get too cold and freeze up, causing blocked airflow. Refrigerant systems are deigned for a specific temperature range, and operation below freezing requires a different design that wouldn't be amenable to performance in hotter temps. Some form of head pressure control would be required.

Last, you would run into issues with the condensate drain freezing and clogging up in freezing weather.

In freezing weather it's much easier to exhaust the humid air, and replace with dry air from outside.

It’s not about heat exchange. It’s about drying the air. EDIT: I just noticed you said that doesn’t happen either.

In order to dry the air the water has to be condensed out of it. If you're going to condense water, you need a cold surface (evaporator) below the dew point temperature to do so. Hence why you need refrigeration to make that cold surface. Heat exchange is required to cool the air and condense water.

 

[Neandrewthal]

Warming fresh air should do it. Even if the 0C exterior air is 100% humidity, when you warm it to 21C/70F the humidity becomes 24% (Google dew point calculator). Not sure what the various defrost and auto settings do as far as mixing in some recirc.

As others have mentioned, liquid water on the floor evaporating could be exacerbating the issue. Maybe turning off vents to your feet can help.

 

[Neandrewthal]

In order to dry the air the water has to be condensed out of it. If you're going to condense water, you need a cold surface (evaporator) below the dew point temperature to do so. Hence why you need refrigeration to make that cold surface. Heat exchange is required to cool the air and condense water.

Not entirely. Simply warming air lowers the relative humidity. See my above post.

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