I think the elephant in the room is calibration of the CO2 detector.<p>When I looked into this a few years ago, I couldn't find any accuracy guaranties for CO2 meters marketed for households / greenhouses.<p>The closest thing I could find were laboratories that could test CO2 meters in chambers with known CO2 concentrations. But IIRC the pricing for those labs was prohibitively expensive.<p>- There were literally <i>no</i> guaranteed accuracy bounds for the meters I looked at. So they could be off by 3x reality for all I know.<p>- Their calibration systems relied on an assumed CO2 concentration for outside air. But even if the calibration system ensured that the meter would report the right number for <i>that</i> CO2 concentration, there was no information about how accurate the calibrated meter would be at <i>other</i> CO2 concentrations. Nor information about how the meter's numbers would be off when the CO2 levels observed during calibration differed from the level assumed by the calibration logic.<p>These limitations might not be a problem for some applications. But they could be an issue when people want to relate <i>their</i> meters' readings to the numbers used in various research publications.
I have a fantastic way that I’ve trained my CO2 sense: an Italian greyhound. Anything above 900ppm and he barks and gets quite frantic above 1100ppm. I’m now able to anticipate the barking and normally realise at about 850ppm that we need to go for a walk and open the windows.<p>A vet friend theorised that because they have a completely disproportionate and crazy cardiopulmonary system (huge lungs and heart compared to overall volume) they are particularly sensitive to CO2 because they inhale more of it and it goes into their blood and brain much faster.<p>As soon as we open a window he calms - in winter I don’t take him out, I just ventilate the room.
CO2 concentrations are an ongoing topic of debate. There are studies that show no measurable cognitive changes up to CO2 concentrations in the thousands of PPM, while other studies seem to show cognitive changes at much lower amounts.<p>I tend to think that people with CO2 sensors tend to over-focus on CO2, when really what they’re feeling is the general stuffiness of a room. CO2 isn’t the only thing that accumulates in the air in an enclosed space, but once you have a CO2 meter in hand you might think it’s the only thing that matters.<p>That said, CO2 levels can be used to somewhat estimate the amount of rebreathing going on in a space. That is, the amount of air that you breathe in that has been exhaled by someone else. It’s not entirely pleasant, which can explain why people feel like they don’t like high CO2 levels
I've been using the uHoo air monitor for the last few months. I have one in the bedroom, living room, and office. It monitors many air factors, but CO2 was my primary focus.<p>My original goal was to have a fresh air intake activate automatically at certain concentration levels, if the outside ambient temperature/humidity were appropriate.<p>However, living in a hot humid place, the data I got made that solution seem futile. Ventilation for CO2 alone takes so much air that it becomes basically a full reset on dehumidifying and conditioning.<p>However, this failure lead me to the fortuitous discovery that by adding 36 hydroponic heads of lettuce, I am now going <i>beyond</i> outside CO2 levels, dipping down to 390-400 and only reaching ~700 overnight when it's the worst.
I've bought [1] and coupled it with Zabbix using [2].<p>Now I have a pretty realtime graph and a strong reasoning to air my room more often.<p>[1] <a href="https://www.tfa-dostmann.de/en/product/co2-monitor-airco2ntrol-mini-31-5006/" rel="nofollow">https://www.tfa-dostmann.de/en/product/co2-monitor-airco2ntr...</a><p>[2] <a href="https://codeberg.org/pf-monitoring/airco2ntrold" rel="nofollow">https://codeberg.org/pf-monitoring/airco2ntrold</a>
I've had an Awair monitor for a few years and enjoy keeping a fairly close eye on the numbers, but from what I've experienced so far I'm convinced sure I'd be able to train myself to discern CO2 levels. If anything it has mostly just encouraged me to open the windows, even just for a bit, whenever possible, and to <i>always</i> use the kitchen exhaust fan with our gas stove (and motivated me to buy an induction range in the future).
> I’m looking forward to the day when I can walk into a room and say, huh, feels like 800 in here...<p>I've been this way for well over a year now. Almost two years ago I picked up an air monitor from Awair (yes, this was a pandemic related purchase because I was working so much from home) and I frequently checked what the CO2 was. Nowadays, as it starts hitting ~750ppm, without looking at the monitor I can tell it feels "stuffy" and I open a window.
Is there any kind of CO2 scrubbing that's at all practical for home? I'm curious what the effects would be of going below ambient/outdoor levels, especially since those are rising (if slowly).
I'm currently playing with 2 NDIR co2 sensors connected to a pi (scd30 and MH-Z14), graphing the data using grafana.<p>Curious what sensor the aranet4 uses.<p>Edit: just found this teardown - <a href="https://kaspars.net/blog/aranet4-teardown" rel="nofollow">https://kaspars.net/blog/aranet4-teardown</a>
I feel terrible above like 900/1000ppm but I’m sure it’s also a good proxy for whatever other garbage and voc’s are in the air. When my monitor reaches 800 I’ll throw my window exhaust fan on for a few hours to circulate the air in my home.
people on supplemental oxygen sometimes get CO2 problems; the oxymeter shows good numbers but they're acting drunk or feeling poorly otherwise.<p>Apparently its sneaky and cumulative; a few moments wont do much but as time goes on you get fizzier.
I have a qingping air monitor lite, which was around $70.<p>It also measures PM10 and PM2,5 which helped me show that my wood furnace is indeed leaking something sometimes when I noticed it smelling weird.
I have a cheap (about $20-25 a couple years ago) sensor from Amazon in my plane. It calibrates itself when I turn it on and I check it works on the ground before every flight - open the window after starting the engine and see co2 going up ;) Granted, I don’t really care about any small errors or small changes - I want the sensors to warn me if co2 concentration goes up significantly (e.g. because of leaks from exhaust system).
I don't know much about LoRa yet, but i would be interested to tinker with it. Can the LoRa radio of the Aranet4 PRO be used by alternative base stations or is it somehow locked down to their own Aranet PRO base station?
We need a study on what will kill you sooner, the CO2 levels or the need to anxiously monitor whether CO2 levels are too high in every single enclosed space you enter.