# How often to open the doors and windows for oxygen replenishment? **URL:** \ **Category:** Factual Questions\ **Created:** [October 17, 2014, 1:25pm UTC](https://boards.straightdope.com/t/how-often-to-open-the-doors-and-windows-for-oxygen-replenishment/701579 "2014-10-17T13:25:04Z")\ **Posts on this page:** 5\ **Page:** 2
**Author:** ![Snnipe\_70E](https://avatars.discourse-cdn.com/v4/letter/s/b5a626/32.png) [@Snnipe\_70E](https://boards.straightdope.com/u/Snnipe_70E)\ **Post date:** [October 18, 2014, 3:35pm UTC](https://boards.straightdope.com/t/how-often-to-open-the-doors-and-windows-for-oxygen-replenishment/701579/21 "2014-10-18T15:35:47Z")
In testing air quality of an office building the first thing that is look at is the CO2 levels. The O2 levels are seldom tested. My former boss and I were traveling in the company mini van with the AC on max. We just happened to have the CO2 meter up front with us. I turned it on. The needle pegged, I do not remember the number but it was pegged. When we opened the windows the level went down to with in proper range. But with the windows closed and on Max AC the CO2 level began to climb. Turned from Max AC to where it was pulling in outside air and the levels dropped down to the healthy range. With a tightly closed up room you will not deprive your brain of O2, but the CO2 levels can climb. One of the symptoms of high CO2 is headaches. Office buildings HVAC systems now have minumn fresh air dampers that do not close completely but let in a small amount of fresh air to keep the CO2 levels down. ---
**Author:** ![Learjeff](https://avatars.discourse-cdn.com/v4/letter/l/94ad74/32.png) [@Learjeff](https://boards.straightdope.com/u/Learjeff)\ **Post date:** [October 18, 2014, 5:27pm UTC](https://boards.straightdope.com/t/how-often-to-open-the-doors-and-windows-for-oxygen-replenishment/701579/22 "2014-10-18T17:27:36Z")
> [@Little\_Nemo](#): > > The real issue is carbon dioxide not oxygen. Right – an important point! > [@Dallas\_Jones](#): > > Get a canary. They are friendly and pretty birds. That worked for miners, didn’t it? 🙂 I lived a large part of my life in Michigan, where it gets cold in the winter, and we do our best to keep the windows and doors shut all winter. To conserve energy, we take additional measures to reduce air exchange, adding seals to doors and windows, etc. I don’t remember anyone suffering from CO2 buildup, or much fuss about it being a serious concern, at least in houses that weren’t designed from the ground up to be as tight as possible. No, the bigger worry was radon gas buildup CO2 concentration is the prim indicator that makes your lungs realize it’s time to work (expel old air and take in fresh air). My guess is that if CO2 levels are high, you’d notice it: you’d breathe heavily and unsatisfactorily (you wouldn’t feel like you got a lung full of nice fresh air). Perhaps CO2 poisoning happens at lower levels, though. > [@Snnipe\_70E](#): > > In testing air quality of an office building the first thing that is look at is the CO2 levels. The O2 levels are seldom tested. My former boss and I were traveling in the company mini van with the AC on max. We just happened to have the CO2 meter up front with us. I turned it on. The needle pegged, I do not remember the number but it was pegged. That’s very interesting; thanks for sharing. But, if this is true, why doesn’t anyone seem to be aware of it? Doesn’t this count as a serious health/safety risk? Did you perhaps have the meter set at a range where “pegged” didn’t mean “dangerous”? ---
**Author:** ![rbroome](https://avatars.discourse-cdn.com/v4/letter/r/838e76/32.png) [@rbroome](https://boards.straightdope.com/u/rbroome)\ **Post date:** [October 18, 2014, 8:14pm UTC](https://boards.straightdope.com/t/how-often-to-open-the-doors-and-windows-for-oxygen-replenishment/701579/23 "2014-10-18T20:14:07Z")
> [@Snnipe\_70E](#): > > In testing air quality of an office building the first thing that is look at is the CO2 levels. The O2 levels are seldom tested. My former boss and I were traveling in the company mini van with the AC on max. We just happened to have the CO2 meter up front with us. I turned it on. The needle pegged, I do not remember the number but it was pegged. When we opened the windows the level went down to with in proper range. But with the windows closed and on Max AC the CO2 level began to climb. Turned from Max AC to where it was pulling in outside air and the levels dropped down to the healthy range. > > With a tightly closed up room you will not deprive your brain of O2, but the CO2 levels can climb. One of the symptoms of high CO2 is headaches. > > Office buildings HVAC systems now have minumn fresh air dampers that do not close completely but let in a small amount of fresh air to keep the CO2 levels down. The story about the automobile surprised me. So I googled: > **[High CO2 Levels Indoors Will Surprise You](https://www.co2meter.com/blogs/news/high-carbon-dioxide-co2-levels-indoors)** > > CO2Meter highlights a Carbon Dioxide (CO2) exposure limits chart and references ASHRAE, OSHA, NIOSH EPA, and more. it is obviously an advertising site for a meter maker, but indicates that there is a real effect here. Alertness and reasoning skills-both important for driving-go down at high CO2 levels. I wonder whether this is a real problem or not. I suspect the automakers have addressed it, but the above test indicate that it might be a problem. ---
**Author:** ![Snnipe\_70E](https://avatars.discourse-cdn.com/v4/letter/s/b5a626/32.png) [@Snnipe\_70E](https://boards.straightdope.com/u/Snnipe_70E)\ **Post date:** [October 18, 2014, 11:13pm UTC](https://boards.straightdope.com/t/how-often-to-open-the-doors-and-windows-for-oxygen-replenishment/701579/24 "2014-10-18T23:13:16Z")
ever go on a long drive with the windows up and the AC on max? Did you end up with a headache? ---
**Author:** ![Siam\_Sam](https://avatars.discourse-cdn.com/v4/letter/s/d78d45/32.png) [@Siam\_Sam](https://boards.straightdope.com/u/Siam_Sam)\ **Post date:** [October 22, 2014, 2:54am UTC](https://boards.straightdope.com/t/how-often-to-open-the-doors-and-windows-for-oxygen-replenishment/701579/25 "2014-10-22T02:54:01Z")
> [@IMfez](#): > > Right now I live in a climate with extreme humidity (Bangkok, Thailand). Closing the windows and doors helps keep out the sticky/moist air and raise the comfort level, but I’m concerned that I might be depriving my brain of oxygen especially during my night hours. > > The room is fairly small, I would guess about 180 square feet. Is running low on oxygen a real concern if I close all the windows and doors for say 16 hours? In Bangkok, I’d be more worried about the filthy air that’s being let in through the open window! I’m assuming air conditioning is not an option. But you must at least have some sort of fan for air circulation. I wouldn’t worry too much about it. [Previous page](https://boards.straightdope.com/t/how-often-to-open-the-doors-and-windows-for-oxygen-replenishment/701579.md?page=1)