Normally a high CO2 level will go hand in hand with the air feeling stuffy from other pollutants that build up at the same time, so there's hardly a need to continuously use a CO2 meter as you can easily notice when the air "goes bad". CO2 buildup is quite predictable in most closed rooms based on the number of people inside, the room volume and the ventilation as well, so you can just work out a ventilation schedule and stick to that instead. Common sense often beats smart gadets.
Personally I have a CO2 meter in my tiny office room but I don't need to look at it as I pretty much know that it will be in the red after being in the room for a while with the door closed.
> Normally a high CO2 level will go hand in hand with... other pollutants that build up at the same time
No, I think you've got that backwards. It's other pollutants that may (but also may not) go hand in hand with CO2.
CO2 is the only pollutant constantly produced by people and that works as the main indicator of air quality.
Things like PM2.5 or VOC levels, if they are being produced at all, will also be trapped in stale air. But my apartment, for example, generates virtually none of those, except for when I'm cooking, when it generates massive quantities of PM2.5.
I use a CO2 monitor in my living room and I adjust the crack in the window several times a day to keep it around 550 without wasting too much on heating. It's not even remotely common sense, you absolutely need a sensor.
> I use a CO2 monitor in my living room and I adjust the crack in the window several times a day to keep it around 550 without wasting too much on heating. It's not even remotely common sense, you absolutely need a sensor.
It's more efficient to air out by opening the windows fully and creating a draft for a few minutes several times a day than to leave the window cracked when it's colder outside.
That's not adequate, at least for me as a relatively average sized man in a relatively average sized living unit. My respiration is sufficient to raise CO2 levels indoors to over 800ppm from background levels within an hour without constant ventilation.
CO2 levels build up higher than I want within half an hour so I'd have to be doing that all day long. And it would result in a periodically freezing apartment.
It's much more efficient for me to keep it open a crack.
Do you have central air, and keep the fan running? I've experimented with this at our place and doing a full cycle for 5 minutes, then turning the fan to "on" rather than "auto" and closing all doors and windows will keep it below 700 everywhere for about 6 hours. Otherwise the second floor climbs into the 1000's while the first floor stays around 500
Thinking about CO2 levels isn't common sense until after you've been keeping an eye on one of these gadgets. After sitting in a meeting room for an hour, people may find it feels warm or stuffy or notice a slight headache, but they won't necessarily draw the connection that they really ought to open a window or door or adjourn the meeting for a few minutes. The importance of breathing fresh air becomes much more common sense after you've learned to tell the difference.
> Normally a high CO2 level will go hand in hand with the air feeling stuffy from other pollutants that build up at the same time, so there's hardly a need to continuously use a CO2 meter as you can easily notice when the air "goes bad"
Strong disagree based on direct experience. I have a HEPA unit that keeps air in the entire living unit clean (from VOCs, particulate matter, NO2, etc.) but doesn't alter CO2 levels. There is little to no human-detectable effect from CO2 levels rising up to 2500ppm (according to my separate CO2 monitor).
HEPA filter does not do much for VOC. VOCs, because they are gases, are about 1000 times smaller than what HEPA filters can capture. You need carbon-based filter to neutralize them.
My unit has both HEPA and carbon-based filters. The point is, my CO2 levels rise independently of any other pollutant and it's not reliably detectable by a human as far as I can tell.
My understanding, admittedly driven by 3D printing, is that they only last about a week before the substrate degrades. Fortunately activated carbon is cheap.
Variable, between 6 months and a year, per the manufacturer's recommendation and unit's ability to sense when the filter needs replacing. It seems like you're saying yours only last a week because you're constantly generating fumes from 3D printing? I don't do anything like that. I would be curious to get some kind of independent measurement of effectiveness of a new filter over time (and I suppose I will from my air monitor next time I replace). But again, the point is my separate air quality monitor shows increases in CO2 that are not associated with rise in any of the other 4 detectable pollutants it measures.
What I’ve been told is that the carbon filter will stop absorbing VOCs after a week, regardless of how much I use the printer. Considering that some of them are carcinogens, I’m not taking any chances.
Presumably this should also hold for other carbon filters, then, but I don’t know how I would verify that.
I went to a lot of trouble to install an ERV — a Panasonic model. Brought my CO2 levels down from consistently over 1200ppm to ~500ppm with people in the house. Hot/humid areas make it difficult to bring in fresh air since the moisture in the air can lead to all sorts of issues and obviously it's very inefficient to have 100 degree air coming into the house when you're seeking mid-70s temps indoors. ERVs are designed to address these issues.
Check out a video here to see how these things work (this demo is an HRV, so it doesn't help with humidity, but you can see how well it works when there is a big temperature difference between indoors and outdoors).
I've wondered about this. If I install an air monitor in my room, what do I do if it shows low quality? Open my window in below-freezing winter temps? Hire someone to overhaul my furnace and vents?
So, this works with temperatures down to freezing and below (don’t know what the cut off is, maybe there is none given this planet’s temperature range) and if you heat and dress appropriately (i.e. not up to super high temperatures – around 20°C or so – and if you have a sweater or jacket on or can put one on).
Obviously you also need the appropriate building for it. (So no fancy passive house. No fancy air conditioning – which is quite uncommon where I’m from anyway.)
Generally, if you only open the windows for five minutes or so the air will cool down substantially (the right moment to pull on that sweater) but everything else (walls, furniture) will not really cool down that much, meaning the room will be quick to be back at an appropriate temperature.
We learned and did this in school, often do it in offices and meeting rooms and also at home. Though, admittedly the temporary unpleasantness does frequently lead to people postponing opening the windows forever and ever. (Once every 90 minutes in a classroom setting might not be enough.)
In those settings a CO2 traffic light as an obvious visual indicator would be super helpful.
If you aren't willing to do anything about it then why bother with the air monitor?
If you only have a single room then your options are limited, however moving rooms or opening a door to a different room and turning on a fan to increase circulation?
If it is CO2 then you could invest in a houseplant or two.
Seems like there'd be a market for a CO2 > O2 exchanger of some sort. I don't know enough chemistry to recognize why this is probably too difficult for commercial viability.
Houseplants do not exchange anything near significant amounts of CO2 for this purpose.
The long term answer is to improve the HVAC: reconfigure for more external air mixing (commercial), or find a way to install an HRV or ERV, or open a window, but that can be expensive or impossible depending on the situation.
I'm currently renovating a house in The Netherlands, we're installing a heat pump and to make the place more efficient we also replaced the glass with triple glazed (but without vents in the frames as they let heat escape). Given that we were effectively making our house a "sealed envelope" we had to add mechanical ventilation (ERV) to ensure proper airflow around the property. As you can imagine, retrofitting ducting around an old house required a LOT of creative work!
Open the window. In my apartment I keep a single open somewhere between a millimeter and a centimeter when it's below freezing, depending on the temperature and wind. That's enough to keep my CO2 sensor happy (try to keep it around 550), and it (shockingly) doesn't seem to affect my heating bill all that much. There's a cold corner of the room next to that window, but the rest of the apartment stays just as warm. (I have a thermostat that controls heating.)
I also keep a humidifier running full blast (silently) because otherwise it will get crazy dry on some days.
> I also keep a humidifier running full blast (silently) because otherwise it will get crazy dry on some days.
Heh, I usually keep the dehumidifier running, I don’t think I’ll ever need a humidifier. Currently, 80% RH (7g/m³) outside, with indoor levels all slightly above 60%.
It doesn't though. The relative humidity at 70°F is only 30-35% with the humidifier running full blast. Because it's often 7-15% without the humidifier. Because the air coming through the window is bone dry.
The problem in the winter here is keeping enough humidity in the air. It would be nice if I ever had to worry about condensation. ;)
if you keep the window open all year, dress appropriately and avoid heated buildings you don't notice how cold it is. I switch it on a few years ago because my cat is getting really old. I now feel cold if its 17 C or below.
That is an extraordinarily climate-specific recommendation. It’s currently a fairly mild 30F/-1 C outside my house and even that is obviously way too cold to go without heat completely.
You are conditioned to think you are and feel cold. Look how cold some countries and regions get? The people working outside there are not a different species. The trick is to get used to it gradually. I didn't say it was fun or easy.
I spend a good bit of winter working outside but with physical activity it is much easier.
Do you have other ideas? I mean, it would be nice? I cant think of anything else besides migration.
As someone from said countries and regions, people living outside freeze to death here. Long before you get to that point your water pipes will freeze, leaving you without running water. The pipes will then burst and flood your house if you don't address it quickly enough. You can certainly heat it to a lower temperature and occasionally crack open a window for some fresh air, but there's a difference between conditioning yourself to be comfortable at 17C and -30C.
>Normally a high CO2 level will go hand in hand with the air feeling stuffy
I bought my Dad a NetAtmo weather station one part is outside and one is inside.
During Christmas with guests over I looked and saw the CO2 was 1000ppm it felt very stuffy (no air handler in an old house). I opened a window and let some fresh cool air in and CO2 out. It felt so much better.
It was nice to know why it felt stuffy. It wasn't just all the turkey and potatoes that I had eaten.
Personally I have a CO2 meter in my tiny office room but I don't need to look at it as I pretty much know that it will be in the red after being in the room for a while with the door closed.