HN Explorer

Ask HN: Do you measure and/or mitigate CO2 in your living space?

98 points by _njuy ↗ HN
If so - how?

Also - has anyone moved away from gas stove since recent articles about the issues with fumes they emit into spaces?

151 comments

[ 2.5 ms ] story [ 189 ms ] thread
shapefrog
> Do you measure

No.

> mitigate CO2 in your living space?

I open the window occasionally and when they are not open the are pretty draughty windows.

dewey
I used to do it by using an Awair device, I could feed it into HomeKit which is why I choose it in the first place. Then some weird crypto thing (planetwatch.io) happend which made them really expensive and I sold it for a lot more than I bought it.

Since then, I don't monitor any more and I don't miss it as I'm always airing the room multiple times per day anyway and I didn't really get something out of it except some pretty graphs.

Jaxan
We borrowed a sensor for a few weeks and measured different rooms. The readings are especially high when we invite people. (We cook electric , and I think the stove has little to do with high CO2 in a living space.)

The conclusion is that we need to ventilate more. Especially in the bedroom. Sometimes it’s hard to find a good balance between ventilation and heating.

Jaxan
I should add: it was rather fancy as it could display graphs and such. But in the end that not very useful, after a few days of watching the readings you start to understand when CO2 increases (people) and decreases (ventilation). It never reached unhealthy levels of CO2 in our home.
jonahbenton
Running an Awair in the kitchen while cooking is enlightening. I run the stove vent fan to mitigate.

There is no good solution for substantially mitigating CO2 in a living space other than ventilation. I also have an AlgenAir, and I love the business, but it can't on its own consume enough CO2 to compete with human production in a closed area. 100 devices- 2000+ plants equivalent- is what the CO2 absorption math says would be needed.

henearkr
The radical step I took was to switch to all-electric cooking, instead of gas.
yosito
Not CO2 specifically, but I bought a fancy detector and air purifier that removes particulate pollution from my living space.
2OEH8eoCRo0
I don't measure but I mitigate. I sleep with the bedroom door open and try to have a window at least cracked as often as possible.
kace91
In my country it is common to start your day by opening all windows for 5-10 minutes. It’s done several times a day sometimes.

I worried about CO2 and general air quality in the office, particularly at those moments when coming back for lunch and noticing a “loaded environment” for lack or a better word. Not a problem anymore thanks to remote work :D

dewey
> Not a problem anymore thanks to remote work :D

I feel like I'm very aware of bad air quality, especially in the office, where many people don't seem to care at all.

Definitely one of the biggest benefits from working at home for me, in the office I always felt exhausted after 1pm just because the air quality was so bad and airing was usually discouraged by angry looking coworkers ;)

caf
I use a kaiterra sensor, and like others have said controlling ventilation is really the only way to mitigate it. We're looking at HRV systems now.
emrvb
Yes I measure.

Since I couldn't find an affordable consumer device, I build one myself. Levels in my living room never really exceed acceptable levels. My house is not airtight and constantly mechanically ventilated.

They have to pry my gas stove from my cold, dead hands. I refuse to accept indoor air quality deteriorates that much when using a proper hood (that means turning it on before igniting your stove).

dotancohen 

  > I refuse to accept indoor air quality deteriorates that much when using a proper hood
You might want to measure this. I actually think that you are correct, but what we think is often wrong.
emrvb
I believe to remember I glanced over some of the articles mentioned and I seem to recall they were about poorly ventilated situations without proper hoods.

That doesn't say much about air quality WITH hoods in general, let alone my situation in particular. Incidentally I was already planning to build a little sensor array, specifically for the kitchen, that would would measure some of the nasty stuff.

But even if I would measure that stove is slowly killing me, I wont give it up. Just like I won't give up my coal fired barbecue.

dotancohen
Some pleasures are certainly worth the risk!
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michaelbuckbee
With respect to a gas stove I've felt very similarly (and still have one), but after seeing a few induction cooktops and how nice they are I'll be looking at one for our next house.
neutronicus
Yeah, I used to prefer gas until we bought an all-electric house. The heating rate on the induction range that came with the house is bananas.

The burners go from 1-10 by halves and on 10 the big burner will boil a big-ass stockpot of water in what feels like a minute or two, and that's all I can use it for. 10 is literally too hot to sear meat, it will char it (and set off the smoke detector, apropos of the thread - it's a townhouse so of course the kitchen is right at the fucking center of mass of the house so the other rooms can have better light). It's also super-responsive and lets me get great heat control, if I go from 5.5 to 4 I can see what's happening in the pan change almost instantly. I never had a really fancy gas stove, but the ones I had were certainly not this responsive (although they sure beat the many crappy electric stoves I had).

It adjusts with buttons instead of a knob, which I kind of hate (a lot harder to work while cooking) but obviously that's not a comment on the heating technology.

emrvb
The induction stoves I've had the "pleasure" of working with were all very efficient to get water boiling. For every other cooking technique they were terrible. Perhaps I had bad luck with the models I encountered. Maybe it was caused by the pans or maybe it is just getting used to it. But the fact they're almost exclusively controlled by buttons is absolutely a deal breaker for me. I can't handle the stress of 4 pans and pots with buttons not responding because of a smudge somewhere or just because f*k me. Not to mention the models that have 2 sets of controls for 4 burners, where you have to select the appropriate burner first. Those abominations have to be designed by someone who only boils eggs or cooks ramen or hates cooking in general.

/rant

neilv
I stopped using my gas stove about 3 years ago, after it seemed to be causing histamine problems. It was only later that read that this was a known problem, rather than only a bizarre correlation I noticed. I now use an electric air fryer toaster oven, which causes only small particle increases.

I recently got a semi-credible-looking non-IoT air quality monitor (CO2, TVOC, PM1, PM2.5, temp, humidity). I can't say how good the self-calibration is, but when the readings vary up/down usually seems to make a lot of sense.

For CO2 (and other air quality concerns in this problematic old student apartment, in a crazy university neighborhood housing market), I almost always have a couple windows cracked open.

And, if I haven't had a central window open wide for awhile, I'll try a large air exchange with outside, by opening many windows wide for a few minutes.

shlant
> after it seemed to be causing histamine problems

Interesting. My wife and I both realized over the pandemic that we are histamine sensitive (her much moreso than me). We have had the symptoms most of our lives but I do wonder is gas stoves make it worse. We stay in places with gas stoves sometimes, often with poor ventilation in the kitchen. I will have to see if there is any correlation of the severity of our symptoms.

emrvb
I've had similar issues, but since I also experienced it near electric stoves it wouldn't be caused by the burning of gas.

I've hypothesized it is caused by overheating cooking oil.

Before induction cooking, gas stoves generally used to be able to provide more heat than electric ones. So its easier to cook hotter and burn more oil with those stoves.

Might be something else entirely in your case.

neilv
FWIW, I was seeing it only with boiling pasta and vegetables in stainless pot on a newish gas stove. (Sometimes draining and then heating with olive oil in it, but on a lower temp.)
qubex
No.

(Chiming in to diminish sample bias.)

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bsenftner
Yes - Aranet CO2 detector; we also carry it into a cars and open our windows when the CO2 in the car gets too high.

We use electric stoves, but would prefer gas.

muxamilian
I have had a "Netatmo" device for some years and it seems to work well. Whenever I use my gas stove the CO2 reading increases.
hprotagonist
I have a lot of houseplants, does that count?
OJFord
Only if 'a lot' means 'it would look like clinically insane hoarding if they were anything but plants'.

(At sane levels, the effect is negligible.)

Cf. recent discussion on amount of daily rosemary growth it would take - https://news.ycombinator.com/item?id=33577929

kylerush
I recently started measuring CO2, Radon, PM (particulate matter) 1.0, PM 2.5, VOC, humidity, temperature, and air pressure with the Airthings Wave connected device.

I have learned a lot while using it for a couple weeks. First, making a fire in your fireplace is great for ambiance but drags air quality down substantially. It eats up oxygen a lot and make the CO2 increase sharply. It also causes very high spikes in particulate matter (both 1.0 and 2.5 micron) from putting the burned byproducts into the air.

I also started improving the energy efficiency of our heating system by fixing spots in the house where cold air comes in. While this results in less energy used to heat the home, it causes CO2 to increase because there isn’t anymore large holes to bring fresh air in. This device helped me learn that CO2 is and energy efficiency are circular problems. The tighter my house is, the more I need to focus on ventilation - exhaust out and fresh air in. It sounds complicated but for me it just means opening windows throughout the house for about 15-30 minutes per day. That alone makes a major difference on everything - Radon, PM 2.5, PM 1.0, CO2, etc.

Lastly just want to mention that it’s amazing to me how fast CO2 levels can rise with just my husband and I in our living room watching a movie. Good ventilation is something I definitely recommend everyone start measuring and working on.

jaclaz
>It sounds complicated but for me it just means opening windows throughout the house for about 15-30 minutes per day.

In practice what our mothers and grandmothers did, without having ever sampled air.

Some old reference:

https://news.ycombinator.com/item?id=25332981

hnbad
I believe the media has recently (ca 2020) taken to call it "German Lüfting" as it was temporarily celebrated as a solution to the ongoing pandemic.
ben_w
My local contacts in Berlin have called it Lüftschlag — air punch.

(Although, who knows, that might just be a weird localism, just like “Guten Nacht, schlaf gut, träum süß von sauren Gurken.” which I was taught in Köln and nobody else I’ve talked to anywhere in Germany recognises, though when I say I learned it in Köln they all go “Oh, Köln, yeah, they’re all crazy like that”.)

nicbou
I've usually heard Stoßlüften (shock ventilation), and it's often part of the lease in Germany. It helps avoid condensation and mold.
hnbad
As a Kölner by birth that localism does ring a faint bell though I wouldn't have said it's a Cologne thing if you had pushed me on it. We do have plenty of localisms due to the historical proximity to France though, and it always amuses me that "Plümo" (duvet) for example is completely unheard of in most of the German-speaking world and is usually replaced with the far less graceful and to me frankly confusing "Oberbett".

But the general term, as a verb, is "Lüften" or specifically "Stoßlüften" for the shorter form that is often mandatory for apartments with modern insulation but lacking a proper vent system to prevent mold.

On a sidenote: an interesting folk etymology exists for the Rhineland word "Fisimatenten", meaning something like "shenanigans", deriving it from French "visite ma tente", literally "visit my tent": the claim is that mothers would advise their daughters to avoid "Fisimatenten" because French soldiers during the Napolean occupation might invite them (in French) into their tents for, well, shenanigans.

funcDropShadow
"Plümo" is definitely used in other cities on the west side of the Rhein. At least in Koblenz and Mainz.
jnxx
> But the general term, as a verb, is "Lüften" or specifically "Stoßlüften" for the shorter form that is often mandatory for apartments with modern insulation but lacking a proper vent system to prevent mold.

Exactly that.

To add, problems with mold are often due to insufficient insulation in some patches of the wall (like near windows), combined with humid air and insufficient ventilation. A properly insulated house should not form mold. But it is necessary to get humidity out, that's correct.

splitbrain
Berlin native here. My mother (also Berlin-born) said "Träum süß von sauren Gurken". So not a cologne-only thing.
thiht
> In practice what our mothers and grandmothers did

Wait, people don't ventilate their home anymore?

altairprime
I wasn’t taught to in the 80s, because we had a drafty home and it wasn’t necessary to do so consciously.
jaclaz
Seemingly many people don't usually, I think it depends on the country/tradition/habits, in the thread I linked to:

https://news.ycombinator.com/item?id=25332981

there are quite a few replies of people that reported how they were not familiar with the concept.

And I have to underline how the evolution of building practices (again that depends greatly on different countries/local uses) generally speaking tends to make houses more airtight than before, so that ventilating should be more needed nowadays (with the exception of mechanically ventilated houses).

ambicapter
There's a ventilation technique that uses heat exchangers to warm the air coming into your house and vice versa (can't think of the correct name for it right now). Something to look into to have the best of both worlds.
hgomersall
Mechanical ventilation with heat-recovery - MVHR.
throw0101c
* HRV: heat recovery ventilator (temperature only)

* ERV: energy† recover ventilator (temp+humidity)

† Actually "enthalpy", but few understand that concept, so for marketing reasons "energy" is used.

amluto
It might help if “enthalpy” as used by HVAC people was closer to what “enthalpy” means in thermodynamics. The closest I can come is that HVAC enthalpy is the enthalpy of the air plus the enthalpy of vaporization of the water vapor in the air.

This is an oddly named but somewhat useful concept for air conditioning because water that condenses onto an A/C coil delivers its enthalpy of vaporization to the air conditioning system. So you can add “latent heat” to “sensible heat” and get a sensible answer.

But this is all a bit silly in the winter. In the winter, the primary consideration is not the energy cost of vaporizing the water in the air. It’s the amount of water in the air, how to get it there, how to keep it there, and how much humidity is safe for the building envelope. I doubt anyone measures humidity in units of BTU/cubic foot.

throw0101c
> It sounds complicated but for me it just means opening windows throughout the house for about 15-30 minutes per day.

Not very useful when it is -10C (or colder) outside.

Current building science best practice can be summed up in the saying "Build tight and ventilate right.".

* https://www.energy.gov/indianenergy/articles/build-tight-ven...

* https://www.nrel.gov/docs/fy03osti/26458.pdf

Building tight prevents conditioned (heated in winter, cooled in summer) inside air from escaping, causing you to lose/waste money. It also prevents bad outside air (bugs, pollen, dust, car pollution, too humid/dry/cold/hot) from coming in.

Ventilating right means taking stale air from bathrooms (humidity) and kitchens (cooking VOCs) and exhausting it, and at the same time bringing in fresh air from outside on your terms: through filters and tempered to match inside conditions. This is usually done with HRV/ERVs.

Harder to do with older homes that need to be renovated, but now part of the building code for new builds in many areas (ASHRAE 62 defines ventilation volume/rate requirements).

drited
Perhaps it would be useful to hear your experience with CO2 assuming you have already implemented these measures in your home?
VoodooJuJu
If it's -10C, then open the windows for 5 minute intervals, not 15-30, that's what I do.
zsolt224
Buy a co2 meter. You have to have windows opened for much more than 5 minutes. Aaaand you have to open them every 40 minutes, even when you sleep. Good luck with that.
sn9
Or you could stick a fan next to the window to increase air flow.
throw0101c
So I've just paid money (and probably created a bunch of carbon emissions) to heat my home, and now I'm supposed to throw that money away?
jnxx
Not exactly. What you heat is the inside of your rooms, and a significant part of that heat can be felt as infrared radiation. When you ventilate in a quick and intensive manner, you exchange the air, which becomes cold for a few minutes but you do not cool down the room - because that takes longer. And the cold air has very little mass, so it is easy to re-heat again, and will be warmed by the walls etc.
heliodor
The energy stored in your walls is much higher than the energy stored in the air. Swapping out all the air for cold one will reduce the total energy stored in your house very little. The walls will reheat the air. Same with letting AC air escape for a minute or two.
dimitar
For smaller homes switching from convection to infrared heating helps a lot, heating the surfaces instead of the air, means that letting the air mix by opening a window is less of a problem.
eastbound
> it causes CO2 to increase because there isn’t anymore large holes to bring fresh air in

Obviously you need the double-entry exchanger: Air comes in at 5°C and is gradually heated at 18°C by the air exiting, which starts at 20° and is cooled down to 7°C. No external energy required, it’s a classic of neutral-passive buildings.

germinalphrase
Open fireplace rather than a wood stove, yes?
OJFord
Not GP, but I assume either is going to be noticeably worse than no fire at all, a closed log burner better than open. It's not going to stop me enjoying a fire though.

I think they're way under-appreciated, by my calculation they're almost at gas boiler prices in terms of £/kWh of effective heat (currently paying 6p/KWh of gas) - and perhaps particularly as someone living alone, 'spot heating' is great - so cosy by the fire in the evening, way hotter than I'd want to heat the whole house (room even) with gas. I just wish I had one in my bedroom (& perhaps bathroom) too, I wouldn't even need central heating (well, maybe I shouldn't be so confident before Jan...).

kylerush
Yep. We have been wanting to get a fireplace insert which would be a major improvement in air quality, managing temperature, and how fast we burn through wood. The estimates we got were $2k for the insert and $2k to install. Still looking into it, but given the cost it’s not something we can move in immediately.
ahaucnx
Yes, it is indeed amazing how fast CO2 levels can increase. This is especially a problem in low-ventilated classrooms.

At AirGradient we measure a lot of classrooms and it is not uncommon to see CO2 levels rising to above 4500ppm just within 2 or 3 hours. We wrote a blog post some time ago highlighting this [1].

[1] https://www.airgradient.com/open-airgradient/blog/we-measure...

dilippkumar
+1 for Airthings wave.

I learned a lot about the ventilation situation at my place by tracking CO2 buildup. I now know that the time I should leave a window open to get CO2 levels indoors to approximate equalize to outdoor levels is 10x longer than what my intuition suggested.

I also discovered that every time I felt the air was “stuffy” and I needed some fresh air, it actually corresponded to a spike in VOx levels. When mom was visiting over summer, we discovered she is also sensitive to VOx levels.

This is my first winter with airthings wave. I’m curious to see how humidity levels are impacted by trying to keep my house warm.

bokohut
Irony in the timing of your post as I too bought an air monitor filtering device a few weeks ago given my interest in measuring things I cannot see that may impact my families health. After several weeks of use and no ‘major’ concerns this past Saturday evening the air quality was hovering just below severe for many hours and the house felt 'stuffy' to me. I checked the devices readings and then asked each child and my SO independently how they felt after taking a deep breath and for generalization purposes they all stated 'stuffy' in a greatly shortened term. With a significant delta in temperature outside and in I too opened all the external doors and we had a slight wind that was then blowing through for about 5 minutes. Within seconds the air quality began to improve and after closing the house back up the air quality for the remainder of the weekend, and even now, has been optimal and everyone has felt much better. It is very interesting to measure something one can otherwise not see, such as one's air quality, and then take action to improve upon that thing which we never before quantified against how we felt which clearly has impacted our health in ways we may never know. Yet again, what you cannot see matters most!
twobitshifter
If you have a properly sized range hood, won’t that pull out the CO2? Maybe you just need to leave it running longer? I could see a CO2 meter helping with this.
adql
Well, the hood on its own will be pushing air out and if system is constructed correctly it would push some air in but people generally turn it on only when there is smoke, not for stuff like "just" boiling something

And even if it is on, the CO2 at least initially won't be super hot and instantly go up; as flame hits the cookware it will cool down to the temperature of it

scld
Turning my hood on full blast every time I use the burner has become a habit for me. I also luckily have my hood attached to an external wall which is directly blowing outside, which I know many don't.
lzaaz
When the air starts feeling thin I simply open the window.
switch007
I’m surprised how many people aren’t sensitive to lack of fresh air. I yawn, get dehydrated, and generally just feel off. I’ve stayed in hotel rooms with no opening windows and barely got an hour’s sleep.
willnonya
No. Never even considered it. I also plan to replace an electric stove with a gas stove in the near future.
Syzygies
Returning to college teaching mid-pandemic, I bought an SAF Aranet4 Home CO2 meter for measuring my classrooms. It mostly lives in my apartment, waiting to alert me in case I didn't realized I was using my gas range.

There's good evidence predating the pandemic that sufficient air exchange can nearly eliminate respiratory disease transmission. Just as they learned long ago in London that one could eliminate cholera by not drinking sewage water, we understand that the air quality and rate of exchange of indoor air should approximate that of outdoor air. We're however too cheap to do anything about this; it will take more deadly pandemics to drive the needed infrastructure changes.

Do you wince at the idea of people in London drinking sewage water? Those ignorant savages? Yeah, that's how people in the future will look back at us, getting colds and worse all the time in indoor air cesspools.

As we breath out CO2, it makes a great way to measure whether we're changing the air in a room fast enough to keep up with occupant breathing. Wilderness air passed 400ppm as part of global warming. My Manhattan apartment is above the Henry Hudson Parkway, and I can tell the time of day and day of week from the effect of traffic on my CO2 meter. I'm lucky to ever get below 450ppm.

The Aranet works far better than a $30 meter at the measurements a $30 meter will make, such as humidity. By appearance and build quality it's in a different league. CO2 is a bonus.

danuker
> I'm lucky to ever get below 450ppm.

Considering Mauna Loa surpassed 420ppm in June 2022, I think 450 for New York City is indeed exceptional.

https://www.co2.earth/

Syzygies
When I can, I run a pair of box fans exhausting through the windows in one room, letting the air in through the windows in the other room. This feels roughly like living on a houseboat, and is how I can read 450ppm.

I'm now at 728ppm after cooking lunch, windows closed. There's a good kitchen exhaust to a roof fan, so I can get that number down a fair ways by cracking a window.

altairprime
Showering for fifteen minutes in my last apartment would push the bathroom CO2 up to 2000ppm, even with the stock weak exhaust fan on, and it would drop slowly for twelve to fifteen hours but never below 1200ppm so long as someone was home. 750 sounds like luxury :)
kylerush
I live an hour drive north of New York City in a small, rural town of about 2,000 people. Large lot sizes, not much going on pollution wise. The lowest my CO2 has been so far is 659. This is when I open the windows for 30 minutes. I haven’t tried anything more aggressive than that. Either our rural, small-town air is worse than NYC for some reason, or the NYC air isn’t that bad? Very interesting.
badpun
Try opening your window for an entire day (e.g. when you're away) and see the result. If it's still above 600, my guess is that the sensor is crappy. Also, apparently some sensors recalibrate themselves against the lowest level they've seen in the past X days - so ventilating heavily may recalibrate it.
smcleod
I run an Aranet4, it's set to alert if the co2 goes over 900ppm which is where I notice a dip in cognition or at least wakefulness.

I use its API to connect to it once a day and download the last 24hrs of logs (it stores 14 days worth on the device).

It's expensive - but it's really the best there is IMO.

I try to open a window on either side of the house when the co2 gets over about 750~

physicalscience
I have several Airthings Wave connected devices, and I also purchased and installed a Panasonic ERV[0], which I have hooked into my HVAC system. Opening windows several times throughout the day was how I used to control the Co2, but in the winter and summer it became a huge hassle with the temp/humidity changes in the house, but with the ERV running 24/7 I will see an empty room drop to 400 ppm fairly quickly after people leave it (Airthings has an app). Generally rooms with people in them hover around 600-800 ppm with the ERV running. The ventilator will keep the humidity/temp levels pretty consistent because it has this cross capillary core that it runs the air through, but I do need a good few humidifiers running in the winter. The ERV also has the benefit of allowing you to control the air pressure in the house, which is useful for radon, as I was unable to get a good radon pump installed without destroying my downstairs (I live in a raised ranch where the "basement" is the first floor). With the positive pressure in my house + constant ventilation I never see the radon levels generally go above .5.

[0]: https://na.panasonic.com/us/home-and-building-solutions/vent...

binkHN
Yes, but I mostly did it like some others around the start of the pandemic due to all the time everyone was spending indoors and I wound up getting a few devices from Awair. After doing this for a couple of years now, at least in my home, CO2 really never rises to the level that it's a concern. This is largely because my HVAC system is configured to circulate the air in my home every 30 minutes regardless of heating or cooling. With this feature off, yes, CO2 does eventually build up to unhealthy levels rather easily in rooms that have doors closed and related. Ultimately, this experiment gave me a greater appreciation for my HVAC system. On a side note, monitoring rising CO2 levels can, well, be used as a detection method to determine whether someone is in a room and for how long they've been there.
fabioyy
there is a ton of devices that do that on amazon. here ( Brazil/beach ) i get only 300-400 ppm, ps: i dont use gas to Cook/shower. everything is elétric