HVAC settings for smoky weather

[rsg123]

I am located about 150 miles south of the Paradise (NorCal) fires. Last night the AQI in my city was nearly 500 (anything over 400 is “hazardous”).
Unfortunately I have a pre-bioweapon defense MS, but wanted to pose a question: since the temperatures are pretty moderate and it’s comfortable to do so, should I just completely shut off the HVAC or would there be a benefit in running the AC on recirculate mode?
So far I have decided to just shut off the system, but the air recirculating through the cabin air filter seems like it could be better. On the other hand it could pull more outside air into the cabin from leaks.

 

[ucmndd]

Difference is likely negligible. I’d keep it on recirc for comfort and at least a little filtration through the cabin filter.

 

[mkc731]

Not sure if this applies to smoke from a forest fire, or to Tesla’s cooling system, but a recent study found that running the A/C improved cabin air quality because the “cold evaporator that is cooling the air as it passes . . . attracts the pollutant particles, and they deposit there, as opposed to diffusing it into the air you're breathing.”
See: Crank the AC, cut in-car pollution: Engineers show how to best reduce pollution exposure during commutes

 

[BigNick]

Prior to v9 you could customize each aspect of the climate controls individually and the settings would stick.

Now you can only set recirculation. But the setting isn’t always sticky. Turning the defroster on will reset it, when it didn’t before.

I keep recirc on almost all of the time to keep odors out. I drive through some farming country on the way to work. Scenic to look at, but sometimes not so great for the nose.

Surprise exhaust/tobacco/manure odors from outside remind me to turn recirc back on. Didn’t have to do this before.

I agree with running the A/C on recirc to keep the fire smoke out.

 

[rsg123]

Surprise exhaust/tobacco/manure odors from outside remind me to turn recirc back on. Didn’t have to do this before.

I also like to keep recirc on at all times and have noticed this behavior with v9, but it’s caused without ever changing any HVAC settings other than temperature. Other than the camera window stuck on the bottom of the screen (which was fixed), that was the most disappointing change in v9.

 

[JohnnyG]

Difference is likely negligible. I’d keep it on recirc for comfort and at least a little filtration through the cabin filter.

The difference is actually more than one would think...

First off, when recirc is on, the air does not go through the filter. The filter is there to filter the outside air entering the cabin.

Having the fan on the highest setting, with recirc off, will force the outside air to be filtered, and will add positive pressure to the cabin, to reduce unfiltered air from seeping through other air gaps in the cabin.

 

[David29]

I for one have not yet figured out how the manual features of HVAC work with v9. I also tried using recirc this weekend, because I was behind a smelly truck. Later when i went to turn it off, it was already off. I wondered if it is timed. In previous cars i have owned (Mercedes Benzes), the recirc would time out after a few minutes, and the owner's manual cautioned that running on recirc for prolonged periods would allow build-up of moisture and possible condensation on the glass, as I recall. Could Tesla be following that approach?

 

[JohnnyG]

I for one have not yet figured out how the manual features of HVAC work with v9. I also tried using recirc this weekend, because I was behind a smelly truck. Later when i went to turn it off, it was already off. I wondered if it is timed. In previous cars i have owned (Mercedes Benzes), the recirc would time out after a few minutes, and the owner's manual cautioned that running on recirc for prolonged periods would allow build-up of moisture and possible condensation on the glass, as I recall. Could Tesla be following that approach?

I keep turning [Dolby ProLogic] on in the audio settings, and when I go back to check, it is off again. Either they are adding timers to all their switches, or V9 is as buggy as a luxury apartment in the Bronx.

I'm heading out here in a little bit for a 40 mile drive. I'll play with it and report back what I find!

 

[rsg123]

I have to say, my Model S is terrible at keeping the smoke out of the cabin. I’ve tried climate control off, AC on with recirc, heat on with recirc, but nothing makes it better—smoke still gets in.
I drove around in our 2014 Honda Odyssey Elite today and I smelled no smoke at all. Both vehicles have K&N cabin air filters. Very disappointing performance which I can only guess is being caused by gaps/leaks which automakers like Honda have had much more time to develop methods to prevent.

 

[rsg123]

The difference is actually more than one would think...

First off, when recirc is on, the air does not go through the filter. The filter is there to filter the outside air entering the cabin.

Having the fan on the highest setting, with recirc off, will force the outside air to be filtered, and will add positive pressure to the cabin, to reduce unfiltered air from seeping through other air gaps in the cabin.

That is interesting. I’ll try it tomorrow and report my (subjective) results. The current AQI in my area is “Hazardous”.

 

[MC408]

Just ran across this yesterday as well. Turned on recirc to try and keep the smoke out. After picking up my kid and driving for 20 minuites, smelled smoke and looked and recirc was off.

Not sure if it turns off when vehicle is turned off or timed out.

Times like these is when biohazard seems like a good option! Lol

 

[JohnnyG]

I tried it twice today. Once was a 25 minute drive. The other was a 20 minute drive. In both cases, the recirc stayed engaged.

It may be disengaging once the car shuts-down. I'll try that later today too...

 

[rsg123]

I tried turning recirc off and fan speed high today, but it was pretty much the same—choking smoke. I was picking up my kids from piano practice so I first went home after work and switched to my old Honda Pilot. Turned recirc on and I couldn’t smell any smoke. Note to self: next Tesla must have biohazard defense.

 

[Boom]

In the bay area (South - between 200-250 AQI today) and been switching between recirc and biohazard defense. Could be a placebo effect I swear, but air feels cleaner in the car than my house!