Defog and A/C

[jhawk74]

In the morning lately, my windows all fog up and I need to put on the defog. Usually I put it on hot for the quick blast and defog. When I turn it off, it gets a bit cold and I noticed that the a/c is turned on with both hot and cold defog.

Is there a way to default back to heat when I turn the defog off?

Additionally, is there a HEAT setting I'm missing to keep the windows defogged while driving?

Thank you!

 

[nickID]

In the morning lately, my windows all fog up and I need to put on the defog. Usually I put it on hot for the quick blast and defog. When I turn it off, it gets a bit cold and I noticed that the a/c is turned on with both hot and cold defog.

Is there a way to default back to heat when I turn the defog off?

Additionally, is there a HEAT setting I'm missing to keep the windows defogged while driving?

Thank you!

The air conditioner is for more than just cooling the interior. It’s also for dehumidifying the interior. So having it on is the most effective way to defog (the blue symbol) or defrost (the red symbol), which is why the AC is engaged for both. I’m not in my car, but if I recall correctly, defrost forces the temperature to “HI”, while defog lets you set the temperature to whatever you want.

Based on what you want to do, sounds like you should press the button one for defog mode (the blue symbol) and adjust the temperature to whatever you want.

 

[WilliamG]

I leave the AC on always in the winter and I recommend everyone does likewise. In fact I’m sure I use AC more in the winter than the summer. I’ve never had my windows fog up for this reason.

Bottom line is that keeping the humidity out of the air is how you prevent fogging your windows up, and that means using AC.

From what I understand, AC usage is very little power consumption (heat is very expensive, by comparison).

 

[TheTonester]

I leave the AC on always in the winter and I recommend everyone does likewise. In fact I’m sure I use AC more in the winter than the summer. I’ve never had my windows fog up for this reason.

Bottom line is that keeping the humidity out of the air is how you prevent fogging your windows up, and that means using AC.

Do you use recirc or fresh air? The reason I ask, earlier this week I had a cold, rainy day. That night my windows were fogging up like crazy. When I used the defog mode the windows would clear, but when I went back to a normal setting they would immediately fog up again, despite the fact that I had AC on. This was frustrating to me because it didn't happen like this in previous cars. And I don't like to use defog constantly because the blower is so loud and you don't get any direct air so you feel a little bit cold. After doing a google search I determined that this may be because I was using recirc instead of outside air. Regardless, the issue is defintely worse in this car than any previous car I've had for whatever reason. Anybody else feel the same way?

 

[WilliamG]

Do you use recirc or fresh air? The reason I ask, earlier this week I had a cold, rainy day. That night my windows were fogging up like crazy. When I used the defog mode the windows would clear, but when I went back to a normal setting they would immediately fog up again, despite the fact that I had AC on. This was frustrating to me because it didn't happen like this in previous cars. And I don't like to use defog constantly because the blower is so loud and you don't get any direct air so you feel a little bit cold. After doing a google search I determined that this may be because I was using recirc instead of outside air. Regardless, the issue is defintely worse in this car than any previous car I've had for whatever reason. Anybody else feel the same way?

I never use recirc. That’s why you’re having issues with fogging. This isn’t unique to Teslas. Leave AC on and recirc off and you’ll likely never have an issue. Take that from someone who lives in a high-humidity location!

My settings: AC on, recirc off. Temp 69F, fan level 2. Air blowing in all directions (manual). I never touch this anymore and should never need to.

 

[TheTonester]

I never use recirc. That’s why you’re having issues with fogging. This isn’t unique to Teslas. Leave AC on and recirc off and you’ll likely never have an issue. Take that from someone who lives in a high-humidity location!

My settings: AC on, recirc off. Temp 69F, fan level 2. Air blowing in all directions (manual). I never touch this anymore and should never need to.

Cool, thanks. I use very similar settings (I do 68) but for some reason I had recirc on. Will switch recirc off and hope I can see out my windows!

 

[XLR82XS]

From what I understand, AC usage is very little power consumption (heat is very expensive, by comparison).

Correct. Heat uses a lot of energy vs. A/C.

 

[nickID]

It’s worth mentioning that you can turn off recirc while using the “auto” setting. You’ll notice there are 3 toggle states for the recirc button when in auto. Changing it doesn’t kick you out of auto, unlike most other climate-related buttons.

 

[jhawk74]

Thanks everyone.
I think the issue was me having recirc on.

 

[mswlogo]

Thanks everyone.
I think the issue was me having recirc on.

I almost always have Recirculate On with A/C (on those fog up days) otherwise your treating outside air which is expensive and it's really hard to lower the humidity if it's damp outside.

If I have recirculate off (fresh air), then I find I don't need A/C that much. But a lot more heat.

Auto never worked great on my Model 3 (mostly because I didn't like how high it often wanted the fan [noisy]). But on my Model X Auto seems to work fairly well. It could be newer software works better on Model 3 too.

Sometimes you can use fresh air with no heat or A/C to keep things clear.

 

[Teedub21]

I just leave it on auto. Seems to work and no fog.

 

[vickh]

Do you use recirc or fresh air? The reason I ask, earlier this week I had a cold, rainy day. That night my windows were fogging up like crazy. When I used the defog mode the windows would clear, but when I went back to a normal setting they would immediately fog up again, despite the fact that I had AC on. This was frustrating to me because it didn't happen like this in previous cars. And I don't like to use defog constantly because the blower is so loud and you don't get any direct air so you feel a little bit cold. After doing a google search I determined that this may be because I was using recirc instead of outside air. Regardless, the issue is defintely worse in this car than any previous car I've had for whatever reason. Anybody else feel the same way?

yes the issue is defintely worse in this car than any previous car I've had for whatever reason. even in PHX (although we've had a really wet winter so far)

Will try the fresh air option as suggested here. Didn't want to use AC, but looks like no other option w/defog.

 

[WilliamG]

yes the issue is defintely worse in this car than any previous car I've had for whatever reason. even in PHX (although we've had a really wet winter so far)

Will try the fresh air option as suggested here. Didn't want to use AC, but looks like no other option w/defog.

I’ve never had my windows fog up in this car, and I live in Seattle, a high-humidity winter location. You NEED to use AC in any car to clear humidity. That’s what AC does!

We should seriously have a sticky so people here know how to use their climate controls correctly, lol.

 

[newtonfb]

Jeez...am I the only one who uses Auto? I just set the temp and let the car do the work, and it does just fine.

 

[TheTonester]

yes the issue is defintely worse in this car than any previous car I've had for whatever reason. even in PHX (although we've had a really wet winter so far)

Will try the fresh air option as suggested here. Didn't want to use AC, but looks like no other option w/defog.

Yes, and I'm surprised more people don't agree. Using fresh air definitely helps though.

 

[WilliamG]

Jeez...am I the only one who uses Auto? I just set the temp and let the car do the work, and it does just fine.

I don't use auto. How can the car know the humidity level inside the cabin?

 

[gecko10x]

Jeez...am I the only one who uses Auto? I just set the temp and let the car do the work, and it does just fine.

Auto is the only way I can seem to keep the car from fogging.

But it uses far more energy than I'd like when it's cool outside. I think it cycles too often... I don't need it to be exactly 69 degrees at all times; I'd much prefer the system attempted to keep it within a 5 degree range using as little energy as possible.

 

[M3BlueGeorgia]

I leave the AC on always in the winter and I recommend everyone does likewise. In fact I’m sure I use AC more in the winter than the summer. I’ve never had my windows fog up for this reason.

Bottom line is that keeping the humidity out of the air is how you prevent fogging your windows up, and that means using AC.

From what I understand, AC usage is very little power consumption (heat is very expensive, by comparison).

I've found that driving in very frigid temps, switching off the A/C seems to help range.