HVAC System and Fogging Windows

[s4wrxttcs]

I've had my R1T since 2022 with no real issues with Interior fogging issues. At least not to a level that concerned me.

But, lately I've noticed the front window fogging in this early fall weather. I'm using an Auto Setting with a temp setting of 70, recirculation off, and a fan speed of low or med. The fogging is independent of the drive length as it happens on short drives and really long drives.

What's really strange is the fogging disappears if I turn on recirculation which seems backwards. The other thing that happens if I turn on recirculation is the interior gets colder.

Another oddity is that if I push the defogging button it gets uncomfortably warm regardless of the temperature setting I have it set to.

My question is whether other people have observed this or if there is something strange going on with my R1T specifically.

I don't recall any issues with previous firmware version. I'm on firmware version 2025.34.01

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[Dasoss]

I've had my R1T since 2022 with no real issues with Interior fogging issues. At least not to a level that concerned me.

But, lately I've noticed the front window fogging in this early fall weather. I'm using an Auto Setting with a temp setting of 70, recirculation off, and a fan speed of low or med. The fogging is independent of the drive length as it happens on short drives and really long drives.

What's really strange is the fogging disappears if I turn on recirculation which seems backwards. The other thing that happens if I turn on recirculation is the interior gets colder.

Another oddity is that if I push the defogging button it gets uncomfortably warm regardless of the temperature setting I have it set to.

My question is whether other people have observed this or if there is something strange going on with my R1T specifically.

I don't recall any issues with previous firmware version. I'm on firmware version 2025.34.01

This is normal behavior. Every car i have ever had does this. You must turn off recycle, if your windows are fogging. Recycling cabin air builds up moisture which will condense on the cold glass. Wth recycle off, outside air is heated or is dehumidifier. Recycle is for quickly heating or cooling at startup. You also use it if there is heavy smoke or dust or if you run over a skunk

 

[cbrcanuck]

This is normal behavior. Every car i have ever had does this. You must turn off recycle, if your windows are fogging. Recycling cabin air builds up moisture which will condense on the cold glass. Wth recycle off, outside air is heated or is dehumidifier. Recycle is for quickly heating or cooling at startup. You also use it if there is heavy smoke or dust or if you run over a skunk

I believe OP knows this, and is seeing the opposite behaviour...

 

[cbrcanuck]

I've had my R1T since 2022 with no real issues with Interior fogging issues. At least not to a level that concerned me.

But, lately I've noticed the front window fogging in this early fall weather. I'm using an Auto Setting with a temp setting of 70, recirculation off, and a fan speed of low or med. The fogging is independent of the drive length as it happens on short drives and really long drives.

What's really strange is the fogging disappears if I turn on recirculation which seems backwards. The other thing that happens if I turn on recirculation is the interior gets colder.

Another oddity is that if I push the defogging button it gets uncomfortably warm regardless of the temperature setting I have it set to.

My question is whether other people have observed this or if there is something strange going on with my R1T specifically.

I don't recall any issues with previous firmware version. I'm on firmware version 2025.34.01

I've noticed the same behaviour lately, which is new to me too. Wasn't an issue in the past. I haven't started to play with settings yet (hadn't tried recycling cabin air), but will start to play around when the fog comes back. But yeah, it heats up really fast when you press that defog button!

 

[Phatman113]

I've had my R1T since 2022 with no real issues with Interior fogging issues. At least not to a level that concerned me.

But, lately I've noticed the front window fogging in this early fall weather. I'm using an Auto Setting with a temp setting of 70, recirculation off, and a fan speed of low or med. The fogging is independent of the drive length as it happens on short drives and really long drives.

What's really strange is the fogging disappears if I turn on recirculation which seems backwards. The other thing that happens if I turn on recirculation is the interior gets colder.

Another oddity is that if I push the defogging button it gets uncomfortably warm regardless of the temperature setting I have it set to.

My question is whether other people have observed this or if there is something strange going on with my R1T specifically.

I don't recall any issues with previous firmware version. I'm on firmware version 2025.34.01

I will say that I've also noticed it as a difference from previous years. (had since Dec '22). i think something in the recent update changed how the fan works, or changes some defaults in some way. If i set the "fan speed" to high and disable the floor vents (all of that was set by Auto, not me) it seems to clear up, but I never had to do that previously.

 

[s4wrxttcs]

This is normal behavior. Every car i have ever had does this. You must turn off recycle, if your windows are fogging. Recycling cabin air builds up moisture which will condense on the cold glass. Wth recycle off, outside air is heated or is dehumidifier. Recycle is for quickly heating or cooling at startup. You also use it if there is heavy smoke or dust or if you run over a skunk

The entire reason of my post is that I'm observing the opposite of this.

What you wrote is the reality I expect to be living in. That's how its supposed to work. For the past 30+ years of my driving experience that's been the truth.

The reality I currently find myself in is the exact opposite, and its truly confounding to me. I thought the Three Body Problem was just science fiction.

At first I was thinking I was misinterpreting the Icon. I thought back to when I was trying to explain to my mom the buttons in her Subaru. That on meant off for certain buttons and she was hopelessly confused.

Unlike that Subaru the Rivian UI is pretty darn good. It clearly shows the mode its in and it clearly showed Air coming in from outside while I was experiencing fogging then disappeared when the icon showed air being recirculated.

I seriously thought about getting a stink bomb and setting it off next to the car to see if the button was reverse of what it should be. But, I'd need two stink bombs to do an A/B comparison.

 

[cbrcanuck]

The entire reason of my post is that I'm observing the opposite of this.

What you wrote is the reality I expect to be living in. That's how its supposed to work. For the past 30+ years of my driving experience that's been the truth.

The reality I currently find myself in is the exact opposite, and its truly confounding to me. I thought the Three Body Problem was just science fiction.

At first I was thinking I was misinterpreting the Icon. I thought back to when I was trying to explain to my mom the buttons in her Subaru. That on meant off for certain buttons and she was hopelessly confused.

Unlike that Subaru the Rivian UI is pretty darn good. It clearly shows the mode its in and it clearly showed Air coming in from outside while I was experiencing fogging then disappeared when the icon showed air being recirculated.

I seriously thought about getting a stink bomb and setting it off next to the car to see if the button was reverse of what it should be. But, I'd need two stink bombs to do an A/B comparison.

I guess that's better than setting off the stink bomb inside?!

 

[Phatman113]

The entire reason of my post is that I'm observing the opposite of this.

What you wrote is the reality I expect to be living in. That's how its supposed to work. For the past 30+ years of my driving experience that's been the truth.

The reality I currently find myself in is the exact opposite, and its truly confounding to me. I thought the Three Body Problem was just science fiction.

At first I was thinking I was misinterpreting the Icon. I thought back to when I was trying to explain to my mom the buttons in her Subaru. That on meant off for certain buttons and she was hopelessly confused.

Unlike that Subaru the Rivian UI is pretty darn good. It clearly shows the mode its in and it clearly showed Air coming in from outside while I was experiencing fogging then disappeared when the icon showed air being recirculated.

I seriously thought about getting a stink bomb and setting it off next to the car to see if the button was reverse of what it should be. But, I'd need two stink bombs to do an A/B comparison.

Perhaps some default changed, and recirculate automatically engages AC for air drying but using outside air doesn't?

I will say that it seems recirculate still works as the buttons indicate, when following a stinky truck, flipping it on the stink goes away. So it's not that it's backwards (on mine at least?) but maybe some other behavior related?

 

[CANCERDOC]

I notice the AC really struggles when set to outside air - the air feels humid and gross even in not so humid Southern California. It is only on recirc that the air feels cool and fresh. It is possible the OP is experiencing the same thing - maybe Rivian borks the AC a little on outside air (which should be the opposite, since the AC should be doing more work with outside air than with recirculating already conditioned air), such that it just can't remove that much moisture.

 

[Phatman113]

I notice the AC really struggles when set to outside air - the air feels humid and gross even in not so humid Southern California. It is only on recirc that the air feels cool and fresh. It is possible the OP is experiencing the same thing - maybe Rivian borks the AC a little on outside air (which should be the opposite, since the AC should be doing more work with outside air than with recirculating already conditioned air), such that it just can't remove that much moisture.

But this is a new situation, right? I don't feel like it used to struggle with outside air...

 

[CANCERDOC]

But this is a new situation, right? I don't feel like it used to struggle with outside air...

I feel it always did this since Day 1.

 

[Phatman113]

I feel it always did this since Day 1.

Interesting. I feel like it's new, but I have no idea.

 

[sr_dipstick]

I’ve experienced this in my 2022 R1T from time to time regardless of season. I’m in the PNW so it’s relatively temperate. I just blast defrost a bit and it’s gone within a few seconds. I thought it might be something with the cabin air filter getting moist, but never really investigated.

 

[RivAW]

I've had my R1T since 2022 with no real issues with Interior fogging issues. At least not to a level that concerned me.

But, lately I've noticed the front window fogging in this early fall weather. I'm using an Auto Setting with a temp setting of 70, recirculation off, and a fan speed of low or med. The fogging is independent of the drive length as it happens on short drives and really long drives.

What's really strange is the fogging disappears if I turn on recirculation which seems backwards. The other thing that happens if I turn on recirculation is the interior gets colder.

Another oddity is that if I push the defogging button it gets uncomfortably warm regardless of the temperature setting I have it set to.

My question is whether other people have observed this or if there is something strange going on with my R1T specifically.

I don't recall any issues with previous firmware version. I'm on firmware version 2025.34.01

Exactly the same for me......

 

[RivAW]

This is normal behavior. Every car i have ever had does this. You must turn off recycle, if your windows are fogging. Recycling cabin air builds up moisture which will condense on the cold glass. Wth recycle off, outside air is heated or is dehumidifier. Recycle is for quickly heating or cooling at startup. You also use it if there is heavy smoke or dust or if you run over a skunk

Yes, but what OP is saying is that in his (and my) R1T it is working opposite....

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