The bottleneck might be the air in the room • Hacker News Board

Re: The bottleneck might be the air in the room

#111

Post by microtonal » Sat, Jul 04, 2026, 9:20 AM UTC

nok22kon wrote: post #109

microtonal wrote: post #102

Earlier quoted context omitted.

No, it is crap. Yes, it is Sensirion, but it uses a thermal conductivity sensor, which is a very indirect method of measuring CO2. One part of the sensor emits heat and the other senses it and the idea is that heat transfer changes with different CO2 concentrations. However, a lot of other factors influence this as well, such as ambient temperature/humidity (which is why the sensor incorporates measurements from an S…

if you just want to know if CO2 is too much, 300ppm precision is fine. I dont need to know the exact level, just give me a green/yellow/red LED and make it cheap so I can have a sensor in every room

No, it's not. You generally want to ventilate an office when you reach 1000ppm, but then the IKEA will often warn you already at 700ppm. 700ppm is fine.

Re: The bottleneck might be the air in the room

#112

Post by bjackman » Sat, Jul 04, 2026, 9:20 AM UTC

deanc wrote: post #13

I’m not saying this isn’t a legitimate concern but this really seems to have exploded amongst the tech community as the next obsession. I see this pop up on X every few weeks. Is the concern about this really based on actual science? Is there empirical data proving people are less productive or are damaging themselves as a result of heightened CO2 levels? And I don’t mean observational epidemiology studies.

IMO it's something where an intervention is often cheap enough that it's worth it even without great evidence.

But also bear in mind that regardless of "are we operating at max effectiveness", OSHA sets a legal limit of 5000ppm in a workplace, and that's about _safety_.

This article is talking about keeping levels below 1000 which is a very high standard IMO (still arguably justified given the studies mentioned). But if you are in a poorly ventilated home office you could easily hit 3000. At that point you are closer to "illegal in the US" than "earth's atmosphere".

So yeah even if you are unconvinced about micro-optimising your CO2 levels there's a very long established argument in favour of at least paying _some_ attention to it.

Re: The bottleneck might be the air in the room

#113

Post by puttycat » Sat, Jul 04, 2026, 9:21 AM UTC

eastbound wrote: post #93

deanc wrote: post #13

I’m not saying this isn’t a legitimate concern but this really seems to have exploded amongst the tech community as the next obsession. I see this pop up on X every few weeks. Is the concern about this really based on actual science? Is there empirical data proving people are less productive or are damaging themselves as a result of heightened CO2 levels? And I don’t mean observational epidemiology studies.

I’ve lived in Australia and France and I’ve always attributed the taller size of Australians to the excellent state of their ventilation in buildings. Vents (and rooms themselves) are systematically bigger than in France, and if you live in a healthy environment, with meat, lots out outdoors during teen age, and correctly ventilated classrooms during their 20 best years, it makes no secret to me that they grew bigger…

France is indeed ridiculously bad at ventilation (not to mention air conditioning). Restaurants, offices, even gyms - most have bad to non-existing ventilation. Coming from the States this is just insanity.

Re: The bottleneck might be the air in the room

#114

Post by Gigachad » Sat, Jul 04, 2026, 9:23 AM UTC

microtonal wrote: post #105

Gigachad wrote: post #37

Earlier quoted context omitted.

I got the ikea sensor, I’d say it’s way more accurate than you need for personal use. I wouldn’t use it as a scientific instrument but it’s well good enough to see if the room is ventilated enough. I was shocked to see just how fast CO2 climbs while in a room, and how just opening the window just a crack was enough to restore the room to baseline co2. The thing runs on usb 5v so the power consumption is negligible. I…

I have HA send me a notification to ventilate my office when the air reaches 1000ppm CO2. The IKEA ALPSTUGA is often off by 300ppm even under 1000ppm. If I'd use it, I'd be getting notifications at 700ppm. It is a thermal conductivity sensor, which is a very indirect way of measuring CO2 and is very sensitive to environment factors. You only get somewhat good readings in lab conditions. Don't by the ALPSTUGA for anyt…

Within 300 ppm is more than good enough. Realistically 1000 ppm is not that bad. The average meeting room is multiples of that.

Also in my experience it’s much more accurate than that.

Re: The bottleneck might be the air in the room

#115

Post by microtonal » Sat, Jul 04, 2026, 9:24 AM UTC

gpt5 wrote: post #6

I really wish a Apple or another major OEM would integrate CO2 monitor into watches or smartphones. Suddenly, everybody would be aware of the CO2 level in the room, get alerts, etc. and the problem will just solve itself. There are so many rooms, classrooms, movie theaters and other places with poor ventilation where you just feel dizzy, or fall asleep, not knowing it was just due to lower oxygen levels in your blood…

I think the issue is that the common tech requires sensors in an air-chamber. E.g. NDIR works by firing IR at a frequency that is absorbed by CO2. A sensor on the other side either measures the amount of IR light that got through (optical NDIR) or pressure/sound waves (photoacoustic NDIR). I guess that it's hard to use any existing sensors, because they are relatively large and probably water could easily get into the chamber.

Would be extremely cool if Apple, Samsung, and others can crack this, though I think they'd have done it already if it was easy.

Re: The bottleneck might be the air in the room

#116

Post by microtonal » Sat, Jul 04, 2026, 9:26 AM UTC

Gigachad wrote: post #114

microtonal wrote: post #105

Earlier quoted context omitted.

I have HA send me a notification to ventilate my office when the air reaches 1000ppm CO2. The IKEA ALPSTUGA is often off by 300ppm even under 1000ppm. If I'd use it, I'd be getting notifications at 700ppm. It is a thermal conductivity sensor, which is a very indirect way of measuring CO2 and is very sensitive to environment factors. You only get somewhat good readings in lab conditions. Don't by the ALPSTUGA for anyt…

Within 300 ppm is more than good enough. Realistically 1000 ppm is not that bad. The average meeting room is multiples of that. Also in my experience it’s much more accurate than that.

I notice that thinking becomes less clear when going above 1000ppm, so I let HA send a notification at 1000ppm. With ALPSTUGA it would send already at 700ppm. By the way, above 1000 the divergences become even larger due to the inaccuracy also being 10% of the ambient CO2 concentration (in optimal circumstances, probably larger IRL). So, suppose you want to be notified at 2000 ppm, the IKEA sensor might already do so at 1500 or 1600 ppm and it continuously drifts, so it's not like you can use a particular offset.

Besides that, what's the point? There are much better meters in a similar price class. As an additional benefit, they can last months or up to a year on two AA batteries.

ALPSTUGA is an inferior product.

Re: The bottleneck might be the air in the room

#117

Post by glub103011 » Sat, Jul 04, 2026, 9:27 AM UTC

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Re: The bottleneck might be the air in the room

#118

Post by yoshuaw » Sat, Jul 04, 2026, 9:30 AM UTC

Liftyee wrote: post #47

legulere wrote: post #33

Earlier quoted context omitted.

I guess the problem is with the price of the sensors. Just look how expensive the Aranet 4 home shown in article is. There are worse devices for less like the IKEA alpstuga. I also don’t know how much electricity they pull.

I would hesitate to say the IKEA is worse. Inside the IKEA is a reputable Sensirion all in one sensor module. It's much cheaper and smaller because the CO2 sensor in it is using different (newer) technology that only released a few years ago from Sensirion. (Upd: the IKEA does have lower accuracy, with ±100 ppm instead of ±30 ppm. From the SEN63C datasheet)

Worse specs? Sure. Worse value? I don't think so. Worse accuracy? Perhaps not either.

A price of 30 EUR makes this sensor really easy to pick up. For the same price as one Aranet (~180 EUR) the typical household can place a sensor in every room of the house. Which provides far more accurate readings for the whole house than just one high-end sensor in one room.

Re: The bottleneck might be the air in the room

#119

Post by nok22kon » Sat, Jul 04, 2026, 9:31 AM UTC

deanc wrote: post #13

I’m not saying this isn’t a legitimate concern but this really seems to have exploded amongst the tech community as the next obsession. I see this pop up on X every few weeks. Is the concern about this really based on actual science? Is there empirical data proving people are less productive or are damaging themselves as a result of heightened CO2 levels? And I don’t mean observational epidemiology studies.

how can you detect without a study if CO2 meters are basically nowhere?

https://pmc.ncbi.nlm.nih.gov/articles/PMC4892924/

Re: The bottleneck might be the air in the room

#120

Post by zerop » Sat, Jul 04, 2026, 9:33 AM UTC

I tend to agree with this observation. I started taking my evening calls (6:30 to 10:30 PM everyday) from my terrace in open air and my overall fatigue became quite less and I feel quite less tired compared to earlier time when I used to take these calls from my room.