Surprising Carbon Dioxide Levels - Using Recirculate on Long Trips

[Fitter30]

To see how tight your house is there is a test for that. Blower door test. Your electric company might offer it with a energy audit. You tube will have videos on it. Erv or hrv are made to bring fresh air into a space tight is tight with 70% heat/ cold temperature transfer between exhaust to fresh air.

 

[BMWTurboDzl]

I read an article the other day about how quickly carbon dioxide levels can climb in a car when recirculating is turned on. Higher levels can lead to headaches, drowsiness, fatigue, and more. Especially not good when on long trips.

My wife and I regularly drive to Wisconsin, driving 18 hours straight through. She's about to embark on a 5k miles' trip on her own, So I bought this CO/CO2 monitor off Amazon. Part of the display flashes green when the CO2 level is less than 700ppm, flash yellow when between 700-1500ppm, and flash red and sound an alarm when over 1500ppm. Playing with it Testing yesterday in my closed-door home office, the CO2 level was close to 1200ppm, so I opened my window and it started dropping some, but stayed above 900. Thinking something must be wrong, I set it outside in the shade, where the level dropped and stayed just over 400, which I read was "normal" for being outside.

I opened all the windows in the house and the levels inside dropped to under 500 after an hour or so, but closed them after the outside temp climbed well past 80. This morning I came upstairs to my office and turned it on. It's currently flashing yellow with a reading of 918 to start my day. Unfortunately, it's still warm outside, so not opening the windows, yet.

She will be taking the monitor with her (I hope she uses it). We've talked about switching off the recirculate once the car cools off to have some fresh air.

I'd never thought about CO2 levels being so high in our home, but here in central Texas, it stays closed up most of the time with the A/C on.

We are constantly warned about, CO levels, but have you checked the CO2 levels where you work, live, and drive?

My house is so drafty that I never have to worry about it.

I should buy one to bring up to my mothers house. We all get sleepy when we're there and I think it's the lack of air rather than the 1k ft in altitude.

 

[SC Maintenance]

Just FYI - the CO2 monitor in the OP's post is on the Prime day deals for 20% off - now $40.. Was in my cart - ordered one.

https://www.amazon.com/dp/B0F4XD5NN4?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1

 

[Number_35]

Dihydrogen monoxide is also very dangerous.

Sometimes I even drink the stuff!

 

[wander2039]

I bit on the Amazon sale SC posted. We both go through spells at home where we don’t feel like doing anything, its kinda a strange lethargic feeling. Curious since our house is so old shouldn’t have issue.

Its been interesting watching the numbers. It was setting above 900 tonight which it never has so I opened the window and its slowly dropping. Usually its around 700 with us in the room, 400 when no one has been home or really windy. The gas stove really makes it jump. Now to wait till winter and see what it does. Old drafty house so shouldn’t need a fresh air intake. Might carry it a few times in our older cars with exhaust leaks just to see how good or bad it is.

 

[oilboy123]

Very interesting topic. I keep recirc on when driving in traffic. I don't like breathing diesel particles etc. But I am always fighting between that and fogging windows etc. So bouncing back to non recirculate.....

 

[97prizm]

I read an article the other day about how quickly carbon dioxide levels can climb in a car when recirculating is turned on. Higher levels can lead to headaches, drowsiness, fatigue, and more. Especially not good when on long trips.

My wife and I regularly drive to Wisconsin, driving 18 hours straight through. She's about to embark on a 5k miles' trip on her own, So I bought this CO/CO2 monitor off Amazon. Part of the display flashes green when the CO2 level is less than 700ppm, flash yellow when between 700-1500ppm, and flash red and sound an alarm when over 1500ppm. Playing with it Testing yesterday in my closed-door home office, the CO2 level was close to 1200ppm, so I opened my window and it started dropping some, but stayed above 900. Thinking something must be wrong, I set it outside in the shade, where the level dropped and stayed just over 400, which I read was "normal" for being outside.

I opened all the windows in the house and the levels inside dropped to under 500 after an hour or so, but closed them after the outside temp climbed well past 80. This morning I came upstairs to my office and turned it on. It's currently flashing yellow with a reading of 918 to start my day. Unfortunately, it's still warm outside, so not opening the windows, yet.

She will be taking the monitor with her (I hope she uses it). We've talked about switching off the recirculate once the car cools off to have some fresh air.

I'd never thought about CO2 levels being so high in our home, but here in central Texas, it stays closed up most of the time with the A/C on.

We are constantly warned about, CO levels, but have you checked the CO2 levels where you work, live, and drive?

I don't think I've ever seen a vehicle so closed up tight that CO2 was an issue. Have you tested for CO? Carbon monoxide is deadly in low concentrations, and can cause hypoxic symptoms without you realizing it.

 

[Burt]

I don't think I've ever seen a vehicle so closed up tight that CO2 was an issue. Have you tested for CO? Carbon monoxide is deadly in low concentrations, and can cause hypoxic symptoms without you realizing it.

The only reason to test CO2 levels is it may be a cheaper proxy for CO levels. Having said that I believe that car manufacturers have taken this into consideration and blend some fresh air in to insure air quality even if there’s five-six passengers in the car. Otherwise they’d face a lot of liability.

 

[SC Maintenance]

The only reason to test CO2 levels is it may be a cheaper proxy for CO levels. Having said that I believe that car manufacturers have taken this into consideration and blend some fresh air in to insure air quality even if there’s five-six passengers in the car. Otherwise they’d face a lot of liability.

100% different things. You won't have a short term medical problem with CO2 up to maybe 5000PPM. Doesn't mean I want to breath anywhere near that all day. Makes you feel poorly.

I have this meter - have been using it in hotels. So far the worst has been about 1200PPM, so not great really. Best like 450 PPM (basically same as outside).

 

[ecotourist]

It sounds like some of you use the recirculate setting routinely. I think that's a really bad idea.

While higher CO2 levels aren't a health threat at typical indoor levels they do make for drowsiness (or so occupational medicine teaching and the text books say) which can't be good for driver awareness. High indoor CO2 levels are commonly associated with "tight building syndrome".

The typical recommendation - add fresh air. I would now add - don't routinely use the recirc setting on your vehicles. As far as I know recirc is intended for rapid cooling of a vehicle that's been sitting in the sun (though I find opening the windows for a few minutes works pretty well too), driving past a pig farm (ew!), or getting stuck in traffic behind a smoky engine.

 

[Brons2]

I read an article the other day about how quickly carbon dioxide levels can climb in a car when recirculating is turned on. Higher levels can lead to headaches, drowsiness, fatigue, and more. Especially not good when on long trips.

My wife and I regularly drive to Wisconsin, driving 18 hours straight through. She's about to embark on a 5k miles' trip on her own, So I bought this CO/CO2 monitor off Amazon. Part of the display flashes green when the CO2 level is less than 700ppm, flash yellow when between 700-1500ppm, and flash red and sound an alarm when over 1500ppm. Playing with it Testing yesterday in my closed-door home office, the CO2 level was close to 1200ppm, so I opened my window and it started dropping some, but stayed above 900. Thinking something must be wrong, I set it outside in the shade, where the level dropped and stayed just over 400, which I read was "normal" for being outside.

I opened all the windows in the house and the levels inside dropped to under 500 after an hour or so, but closed them after the outside temp climbed well past 80. This morning I came upstairs to my office and turned it on. It's currently flashing yellow with a reading of 918 to start my day. Unfortunately, it's still warm outside, so not opening the windows, yet.

She will be taking the monitor with her (I hope she uses it). We've talked about switching off the recirculate once the car cools off to have some fresh air.

I'd never thought about CO2 levels being so high in our home, but here in central Texas, it stays closed up most of the time with the A/C on.

We are constantly warned about, CO levels, but have you checked the CO2 levels where you work, live, and drive?

I've had cars in the past with weak AC where the interior wasn't cold enough in the summertime unless you left it on recirculate all the time. I'd do it again to stay comfortable.

Now my current truck, has excellent AC on non-recirculate mode and I rarely use recirculate. Instead, I use the phone app to start the AC ahead of time, especially when I'm on the local commuter train, I turn on the AC about 10 minutes before my stop and that works really well for me.

 

[SC Maintenance]

I've had cars in the past with weak AC where the interior wasn't cold enough in the summertime unless you left it on recirculate all the time. I'd do it again to stay comfortable.

Now my current truck, has excellent AC on non-recirculate mode and I rarely use recirculate. Instead, I use the phone app to start the AC ahead of time, especially when I'm on the local commuter train, I turn on the AC about 10 minutes before my stop and that works really well for me.

Here in the summer when its high 90 with 50% humidity your not going to get to 72 with the fresh air vents open - too much humidity to ring out. Once you get to temp you can switch to outdoor air, for a while at least.

 

[Hohn]

I read an article the other day about how quickly carbon dioxide levels can climb in a car when recirculating is turned on. Higher levels can lead to headaches, drowsiness, fatigue, and more. Especially not good when on long trips.

My wife and I regularly drive to Wisconsin, driving 18 hours straight through. She's about to embark on a 5k miles' trip on her own, So I bought this CO/CO2 monitor off Amazon. Part of the display flashes green when the CO2 level is less than 700ppm, flash yellow when between 700-1500ppm, and flash red and sound an alarm when over 1500ppm. Playing with it Testing yesterday in my closed-door home office, the CO2 level was close to 1200ppm, so I opened my window and it started dropping some, but stayed above 900. Thinking something must be wrong, I set it outside in the shade, where the level dropped and stayed just over 400, which I read was "normal" for being outside.

I opened all the windows in the house and the levels inside dropped to under 500 after an hour or so, but closed them after the outside temp climbed well past 80. This morning I came upstairs to my office and turned it on. It's currently flashing yellow with a reading of 918 to start my day. Unfortunately, it's still warm outside, so not opening the windows, yet.

She will be taking the monitor with her (I hope she uses it). We've talked about switching off the recirculate once the car cools off to have some fresh air.

I'd never thought about CO2 levels being so high in our home, but here in central Texas, it stays closed up most of the time with the A/C on.

We are constantly warned about, CO levels, but have you checked the CO2 levels where you work, live, and drive?

And you’re basing all this on a $50 amazon meter that you can’t cross check or calibrate? The golden rule is first verify your measurement system.

What does it read at the tailpipe? In open air?

 

[SC Maintenance]

And you’re basing all this on a $50 amazon meter that you can’t cross check or calibrate? The golden rule is first verify your measurement system.

What does it read at the tailpipe? In open air?

Set it outside and it goes pretty quickly to 400 - 450. I have done this in several places, here, Florida, etc.

Inside it seems to range pretty quickly. My house ranges from 600 - 800 depending on the room.

Like I said, worst hotel room was 1200PPM. It was a small room with the door shut and very little outdoor air - whatever the fan coil pulled in which likely wasn't much.

If you breath directly on it for a while it will alarm / well over 1500 pretty quickly.

I am sure its not +/-1PPM - but I am pretty sure its +/- 100 PPM for sure, more likely +/- 50PPM or better is my guess.

 

[dbias]

I almost never use recir as I keep my GTI and Jeep in the garage so they begin the day around 70 degrees.
Even if parked outside in the heat I long press unlock and roll all four windows down as I approach the car so it’s tolerable once I get in and leave them down for a couple blocks as the ac is pushing the hot air out of the dash.
Whether it’s CO2 or CO length of exposure in an ordinary car is important and occasionally cracking a window or cycling the recir off should be sufficient.

 

[Burt]

And you’re basing all this on a $50 amazon meter that you can’t cross check or calibrate? The golden rule is first verify your measurement system.

What does it read at the tailpipe? In open air?

He said the outdoor readings were 400 ppm which foots. Indoor readings were inline with expectations. How accurate do you need in this circumstance?

 

[Snagglefoot]

I find the recirculate mode helps with the air conditioning in the vehicle which makes sense in that you are cooling air that is at 70 F instead of 90 F. Every bit helps if the system is fairly old and maybe not up to snuff.

 

[SC Maintenance]

He said the outdoor readings were 400 ppm which foots. Indoor readings were inline with expectations. How accurate do you need in this circumstance?

Its probably pretty accurate anyway. It likely uses a infrared LED and a cheap cmos sensor. As the LED gets dirty and the cmos surface oxidizes response will slow, and eventually won't work very well on the higher end. Could be a year, could be 5 years - will see. Until then it seems pretty repeatable to me - which is a pretty good sign for instrumentation.

 

[Donald]

I read an article the other day about how quickly carbon dioxide levels can climb in a car when recirculating is turned on. Higher levels can lead to headaches, drowsiness, fatigue, and more. Especially not good when on long trips.

My wife and I regularly drive to Wisconsin, driving 18 hours straight through. She's about to embark on a 5k miles' trip on her own, So I bought this CO/CO2 monitor off Amazon. Part of the display flashes green when the CO2 level is less than 700ppm, flash yellow when between 700-1500ppm, and flash red and sound an alarm when over 1500ppm. Playing with it Testing yesterday in my closed-door home office, the CO2 level was close to 1200ppm, so I opened my window and it started dropping some, but stayed above 900. Thinking something must be wrong, I set it outside in the shade, where the level dropped and stayed just over 400, which I read was "normal" for being outside.

I opened all the windows in the house and the levels inside dropped to under 500 after an hour or so, but closed them after the outside temp climbed well past 80. This morning I came upstairs to my office and turned it on. It's currently flashing yellow with a reading of 918 to start my day. Unfortunately, it's still warm outside, so not opening the windows, yet.

She will be taking the monitor with her (I hope she uses it). We've talked about switching off the recirculate once the car cools off to have some fresh air.

I'd never thought about CO2 levels being so high in our home, but here in central Texas, it stays closed up most of the time with the A/C on.

We are constantly warned about, CO levels, but have you checked the CO2 levels where you work, live, and drive?

Gas stove? Gas heat?

 

[Donald]

So I heard (on NPR Car Talk) that normal mode does some recirculation and recirculation mode pulls in some fresh air. Neither is 100%.

But there can always be exhaust leaks that can get exhaust into the car but would seem that's more likely when parked with engine running than driving.