Carbon Dioxide levels inside cabin while using HVAC in Auto mode

[Ric G]

I didn't write this, I don't follow facebook and maybe old news but didn't see it posted here...


We talk so much about EV range, performance specs, and software updates, but how often do we think about the actual air we’re breathing inside these machines? Turns out, one Rivian R1T owner did, and what he found might point to a gap in how automakers like Rivian approach cabin air quality. So I was scrolling through the “RIVIAN Electric Vehicles Discussion” group on Facebook this morning and came across a post by Benjamin Ponds. Benjamin had been monitoring the CO₂ levels inside his Rivian R1T using two calibrated meters. He discovered that, during typical driving conditions with the HVAC system set to auto mode, CO₂ concentrations inside the cabin would rise. It would often exceed 2,000 ppm within 30 minutes of driving, and when idling in traffic, levels climbed as high as 3,000 ppm. This raised a serious question in his mind: are Rivian’s HVAC engineers truly prioritizing the air we breathe inside these otherwise forward-thinking electric trucks?

Here’s Benjamin’s full post that brought the issue into focus:

“I have been monitoring CO₂ levels inside my R1T while driving and working this past week. I'm using two different meters simultaneously to verify I'm getting fairly accurate readings, and both have recently been recalibrated to ambient air which is typically around 400 ppm. My typical day can include a 45min–2hr trip, then easily 5–8 stops during the day, and then I ride home. I'm testing with the climate on auto mode. In the mornings, the cabin is usually in the 600 ppm range. Driving solo, the meter with the fastest sensor beeps first warning of 1,500 ppm within 25 minutes of driving. With the family, it happens in 15 minutes. At the 30-minute mark, it alerts at the next warning level, with one exception over the last week, of crossing 2,000 ppm even when solo driving.
When sitting in the truck in traffic, making calls, etc. for 20 minutes, it reaches 2,700–2,900 ppm. I've noticed that on auto mode, the truck will occasionally switch to fresh air and the level drops to the 1,300–1,500 ppm range for a few minutes, then climbs back to the low 2,000s. As I sit here now in the truck for 25 minutes, the faster response sensor just alerted 3,000 ppm. Climate is on auto and hasn't been touched other than temperature all day.
These results do not prove but definitely support my hypothesis that Rivian engineers have not taken CO₂ level control seriously, and they need to revamp the HVAC controls to support a human-friendly cabin environment. All medical documentation I've found, common respiratory recommendations, etc. have drowsiness beginning at 1,000 ppm CO₂ for many people, and that's the recommended level to stay under for prolonged periods. Over 2,000 ppm is sometimes associated with dizziness, brain fog, etc. It gets more drastic as the ppm count rises and exposure time rises, obviously. Manually switching climate to fresh air intake makes the CO₂ ppm count drop from 3,000 ppm to under 600 ppm within 5 minutes. So my original observation and frustration post about the climate constantly 'choosing' recirculate being a potential hazard seems to be grounded in logic, truth, backed by real data, and a concern of habitable environments for modern medicine as well.” He even provided a link to support his research of the potential health trade offs.

https://www.torquenews.com/18003/iv...ivian-r1t-and-what-i-found-supports-my-theory

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[Nixapatfan]

Sounds like someone just has too much time and equipment on their hands. Maybe just set the mode to always pull in outside air or open a window and not worry about it

 

[lefkonj]

Would be curious if he did this test on another dozen random vehicles what the readings would be. Maybe it isn't a Rivian thing but a thing in general.

I have not noticed any negative effects to these things but hey who am I? No seriously who am I again?

 

[Jonger1150]

I don't think this is a Rivian specific problem. Using cabin recirculation causes this.

 

[savethemanual]

Curious what other vehicles test out at.... I've always wondered about this with how airtight cabins are now, I know they have to have the damper to relieve pressure when doors shut so it won't cause damage. Also, a PM 2.5 monitor would be welcome for the HVAC system.

 

[Ric G]

Would be curious if he did this test on another dozen random vehicles what the readings would be. Maybe it isn't a Rivian thing but a thing in general.

I have not noticed any negative effects to these things but hey who am I? No seriously who am I again?

It's OK, s00n FSD will take over when we pass out. LOL

 

[captainjp]

Sounds like someone just has too much time and equipment on their hands. Maybe just set the mode to always pull in outside air or open a window and not worry about it

Oh!! No wonder I feel so lightheaded in my Rivian. Seriously. This is one of the dumbest things I’ve ever heard. What an idiot

 

[Thedude]

Also, a PM 2.5 monitor would be welcome for the HVAC system.

That would just stay pegged out red here all winter.

 

[COdogman]

Someone needs a new hobby.

 

[mikehmb]

I bought a CO2 meter for funsies a few years ago. This would happen in any vehicle, and closed room ... any confined space with a human in it will result in high CO2 levels.

Open a window.

Whoever called out Rivian specifically is either on a hit job or has zero fundamental understanding of ... <gestures broadly> ... anything.

 

[Singletracker]

I have a solution. Quit breathing. That’s probably the source of the CO2. If you’re recycling the cabin air, with no windows cracked open, it seems reasonable that the CO2 levels will build up.

 

[captainjp]

How about he gets a carbon monoxide detector and sits inside an idling ICE vehicle with the recirc off?

Hmmm, I wonder what his findings would be…

 

[NY_Rob]

Maybe keep it on recirculate for the first several min if the cab is really hot, then switch to "normal" once the cab cools down. Isn't that what most folks do anyway?

 

[iansriv]

This would help explain a lot of my behaviour. I will mansplain this to my wife.

Seriously though, I always recirculate the air in all cars. I'm going to change that going forward. This is helpful information. Thanks OP.

 

[Dave Cundiff]

For comparison, Health Canada recommends a time-weighted carbon dioxide average of 1000 ppm -- averaged over a 24-hour period! -- for indoor air (https://www.canada.ca/en/health-canada/services/publications/healthy-living/carbon-dioxide-home.html).

This five-page monograph from Washington State University appears to be an "oldie but goodie" from 2000. It explains some of the engineering and health impacts of carbon dioxide concisely and clearly: https://www.energy.wsu.edu/documents/co2inbuildings.pdf .

This issue wouldn't be my priority, and Mr. Ponds' original complaint has a rather breathless tone (because emotion drives clicks?), but this is interesting information and may be useful to some. I wouldn't be surprised to see Rivian address automatic ventilation in a future software update.

Best wishes!

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