5 ms·

Ask HN: What indoor CO2 monitor do you recommend?

48 points by nequo 2y ago

Those of you who have used CO2 monitors to track your air quality indoors, what product do you recommend?

taf2 2y ago
I had fun with this one https://www.adafruit.com/product/5187 https://www.adafruit.com/product/5187 I used a tiny pico and display to make a little clock/sensor
JSDevOps 2y ago
https://aranet.com/products/aranet4-home https://aranet.com/products/aranet4-home
- aloisdg 2y ago
  Second this one. I own it and it is great
- packetlost 2y ago
  Yeah, I have this one and it's fantastic
- agwa 2y ago
  These are great. I have two of them and access the readings over Bluetooth using some Python code: https://github.com/Anrijs/Aranet4-Python https://github.com/Anrijs/Aranet4-Python (there's also a mobile app which I've never used) The eink display is really nice and if you disable Bluetooth the battery seems to last forever. It's 40% off right now which makes me tempted to pick up a third!
  - hipadev23 2y ago
    That 40% off is a bit misleading, more like 10% off, as you've been able to get them for ~$165 on Amazon forever.
  - jdoss 2y ago
    This python code looks fantastic. Worked right out of the gate. Thanks! Also I was not aware of the Aranet Radiation sensor. There goes some of my fun budget towards picking one of these up.
    - throwaranay4933 2y ago
      Also there is a Go equivalent (https://pkg.go.dev/sbinet.org/x/aranet4 https://pkg.go.dev/sbinet.org/x/aranet4) which works well on Linux and https://github.com/ryansouza/aranet4-exporter-go https://github.com/ryansouza/aranet4-exporter-go can be used to export the data to prometheus.
- zerojames 2y ago
  The Aranet is wonderful. I have had mine (Aranet 4) running for at least a year on a single charge.
- joeyagreco 2y ago
  I've had mine for 3 years now and it's great. Highly recommend.
- Mountain_Skies 2y ago
  Looks like it got the Hug of Death. Amazon sells it so just search for Aranet4 if the manufacturer's site is still struggling.
- EA-3167 2y ago
  I have one of these and have had zero problems, it's easy to use and seemingly very accurate. Incredible battery life too.
- blankx32 2y ago
  Does the app require any clouds to work?
  - agwa 2y ago
    No, for the home version the app just connects over Bluetooth. The protocol is documented and there are robust open source implementations such as https://github.com/Anrijs/Aranet4-Python https://github.com/Anrijs/Aranet4-Python
- unsupp0rted 2y ago
  I'd love to buy one, but it costs `undefined` USD and won't add to cart
mrsirduke 2y ago
I've been happy with the awair element[1] for years. It also measures PM2 and temp/humidity/voc. [1]: https://www.getawair.com/products/element https://www.getawair.com/products/element
- huevosabio 2y ago
  I was happy with my awair until it died after a mere year and a half from purchase. Now its just an expensive brick.
  - ailurooo 2y ago
    yeah that was my experience as well : (
phinnaeus 2y ago
I picked up a pair (indoor+outdoor) of https://www.airgradient.com https://www.airgradient.com monitors a few months ago. Happy with them so far though I have not decided on their final positions.
- tomek_ycomb 2y ago
  Excellent information from the person(s?) running air gradient with regards to pm sensor tech and design. Blog posts, etc. Ranges of kits from pre assembled to solder-yourself, that HN might like. (I am happy with my unit I gave to a friend with a wood fire stove heated house, and built one from kit to save some $ another time.)
  - ds_opseeker 2y ago
    I'll second air gradient. Founder is really cool and supportive. Tech works. I bought some boards from him a while back, ordered the parts of off alibaba, and had a working ESP32 setup in short order.
- mtlynch 2y ago
  I also own an indoor AirGradient, and I like supporting open-source, open hardware, but I've been pretty disappointed with the product. There were no instructions in the box, and I had to dig around a while until I found this PDF from three years ago.[0] I normally can figure out a gadget without reading instructions, but this wasn't self-explanatory, as there are no inputs on the device itself, and I had to figure out how to connect it to my WiFi. It's open-source, but there are no official instructions for re-flashing the device. I had to piece the process together from third-party blog posts. The code itself is pretty low quality. They use tons of globals that could trivially be local variables, and they throw away precision of floats by casting them to ints. I fixed a bunch of bugs in my fork[1] and started contributing them upstream, and the maintainer told me that they just did a giant rewrite, so I'd have to re-do all my changes.[2] I get that it happens, but I would have preferred they announce in the README that the code is deprecated and not to work on it until this rewrite is complete. I still think it's fine overall and I'd probably buy it again for other rooms in my house, but I hope they get their act together a bit more. [0] https://www.airgradient.com/documents/AirGradient%20Manual%2012APR2021.pdf https://www.airgradient.com/documents/AirGradient%20Manual%2... [1] https://github.com/mtlynch/airgradient-arduino https://github.com/mtlynch/airgradient-arduino [2] https://github.com/airgradienthq/arduino/pull/45 https://github.com/airgradienthq/arduino/pull/45
huseyinkeles 2y ago
If you want to go DIY route; I use MH-Z19 sensor along with an ESP-32 which has ESP-Home installed on it, works very well and I log the data on Home Assistant.
sschueller 2y ago
I really like the airthings view plus which also measures radon. https://www.airthings.com/en/view-plus https://www.airthings.com/en/view-plus
- xnx 2y ago
  Seconded. Nice app that has good historical views and easy export of all data.
- azamba 2y ago
  +1 Airthings as long as you don't need any customer support.
- pawelduda 2y ago
  Been running the wave plus for 2 years and can recommend
- sliken 2y ago
  They have a github if you want to use it with your own graphana without requiring any cloud access: https://github.com/Airthings https://github.com/Airthings I've got one per floor in a 3 floor house and all get to the BT -> wifi gateway reliably.
anfractuosity 2y ago
I've used a Sensirion SCD30 (NDIR) sensor attached to a Pi running Grafana, which can be connected to via a web browser.
shagie 2y ago
There's a couple things here and it depends on your needs. The word "track" suggests history. I've got a https://www.amazon.com/gp/product/B0861777SL https://www.amazon.com/gp/product/B0861777SL which does what it says on the box and works. I've got one in my WFH office and one in my bedroom. There are times when I've woken up from a restless sleep to see that at a higher number (especially in the winter when the house is a bit more closed up). Also the track where I can look at the history and see things "oh yea, last about 4h after I cooked dinner the CO2 went up a bit." However, that's only the standard sensor stuff (temp, humidity, CO2). If you've got amazon devices, I've got https://www.amazon.com/gp/product/B08W8KS8D3 https://www.amazon.com/gp/product/B08W8KS8D3 ( Amazon Smart Air Quality Monitor ) which sits in my kitchen because I'm interested in other things there too. I've had some https://milacares.com https://milacares.com air purifiers in the house. They work as air monitors and purifiers. I had some issues with them, but they worked for a good while. Consider if you want instant or historical data. Do you want other data too? What integrations do you have in the house with other home automation? How much DIY are you going to engage in?
whalesalad 2y ago
I have been using one of these for years and it is quite nice. https://www.hydrofarm.com/p/autopilot-desktop-co2-monitor-data-logger/apcem2 https://www.hydrofarm.com/p/autopilot-desktop-co2-monitor-da...
- OutOfHere 2y ago
  A simple setting needs to be configured in it to change the threshold for alerts from that of an indoor marijuana farm to a regular home :-)
  - whalesalad 2y ago
    I'm at 1500ppm right now. Time to open all the windows and let the heat in :\
    - OutOfHere 2y ago
      If using an AC, it is okay to keep the AC running with the window slightly open. This slows down the CO2 buildup while preserving most of the cooling. I would never go over 770 ppm though. Also, the Energy Saver mode of an AC obviously results in a much worse indoor CO2 level.
hedora 2y ago
If you don't want to go the DIY route, and also are interested in a weather station, Ambient Weather is great. It just works out of the box (the CO2 sensor is an add on), and supports a large pile of local APIs and cloud service integrations. We went with one of the fancier models, including a nice LCD display and a solid state (ultrasonic) wind monitor, since we get hurricane-level gusts around here. It's held up fine so far. One annoyance: At least the last time I checked, all the sensors have to be in radio range of the base station. It'd be nice if they had WiFi bridges so we could monitor multiple buildings, etc, with one system.
- AtlasBarfed 2y ago
  The sad reality of consumer IoT is that you will diy eventually. If you start out with a magically integrated system, well, just wait a few years. Hope you thoroughly document your house for its next owner!
mrweasel 2y ago
I've been looking at the Eve Room, but haven't gotten it yet. It's one of the only devices I found that seems to work with HomeKit.
- danudey 2y ago
  I have an Eve Room and I quite like it. The little e-ink display is incredibly easy to read in most lighting conditions (i.e. any condition where there's some light), and the battery life is really fantastic. I also have an air monitor from Qingping[0] which I got from Amazon, and I quite like that as well. Instead of VOCs, it reports pm2.5 and pm10 particulate, which was important for us (in Vancouver) because of the advent of 'wildfire season' in the past few years. I think I would prefer to have the pm2.5/pm10 sensors in the living room and bedrooms (which have windows and where people spent the most time) and the VOC sensors in the kitchen (where cooking/burning happens) and bathroom (where cleaning products are used but ventilation is poor) but I haven't gotten around to buying more of everything yet. [0] https://www.amazon.ca/gp/product/B092HK4BB1/ https://www.amazon.ca/gp/product/B092HK4BB1/
sofixa 2y ago
I have Apollo Automation MSR-1 (it does multiple things, including CO2 and mmWave movement/presence detection; they also have AIR-1 which tracks all sorts of air quality metrics such as VOC etc), flashed with ESPHome reporting to my Home Assistant setup. It's main advantage is that it's extremely affordable compared to the competition, and entirely local. Also I have a Netatmo Indoor Air Quality Monitor (requires their cloud service to work, but there's a Home Assistant integration too) which, alongside PM2.5 and CO2, also does sound and alerts me when music/etc. is too loud.
- radicality 2y ago
  That looks like a nice all-in-one. If anyone from Apollo Automation reading it, perhaps you could also offer a version with the improved scd41 sensor vs the scd40.
londons_explore 2y ago
MH-Z19 module and a WiFi Arduino (esp32) which dumps co2 and temperature into Prometheus. It's like 20 lines of code and very rewarding to write.
crazygringo 2y ago
If you want something that looks attractive in your room and has an app to view history (so the opposite of "hacker"), I highly recommend Awair, been using it for years: https://www.getawair.com/products/element https://www.getawair.com/products/element You can configure the device display to just show numerical CO2 (that's what I do). Seeing the CO2 history graphed on your phone might not seem like it's all that necessary, but I find it really is -- you can see how it falls when you're out, you can see how quickly it skyrockets when you turn on the oven, you can see how long it takes to settle into a steady state overnight. Seeing CO2 over time gives me a conceptual understanding of what's actually happening, which I didn't have with my previous CO2 monitor that just showed the current value.
zeke_the_cat 2y ago
The GQ Electronics GMC-520 has been very reliable for me. It has a Geiger counter and other functionality also.
blankx32 2y ago
Some good input on this thread such as that from brendangregg - https://news.ycombinator.com/item?id=34648021 https://news.ycombinator.com/item?id=34648021
licebmi__at__ 2y ago
Genuinely curious, what are the advantages of a CO2 monitor? I mean, I get you can “track air quality” but what exactly does that mean on day to day basis?
- crazygringo 2y ago
  It means you know when to open the windows more to maintain fresh air. I think much better and am in a better mood when CO2 levels are lower, or when air is fresher generally (the two generally correlate). But I don't want to keep my windows wide open all the time because that wastes AC or heat. So if the monitor is reading above 650, I open windows a little bit. If it's reading over 800, I open them wider. If it's under 550, I'll go back to closing them. It's just a few times a day, but it really helps. And it's not something I can "tell" otherwise easily, because if I have brain fog or am in a bad mood then high CO2 is just one of many possible reasons -- is my blood sugar low? Did I get enough sleep? Etc. A CO2 monitor feels just as essential to my health as weighing myself every day, no bright or blue lights two hours before bed, not overeating carbs, and so forth. It really helps with my overall alertness and productivity in a major way.
  - moooo99 2y ago
    I‘m genuinely curious, but isn’t a CO2 sensor an unnecessary high tech solution considering you could just open your window once a day for a few minutes and let the air exchange?
- zefhous 2y ago
  DHH gave a talk about this a while ago with good citations to studies about CO2 concentration and other VOCs. https://www.youtube.com/watch?v=MRqh8oLY7Ik https://www.youtube.com/watch?v=MRqh8oLY7Ik
amluto 2y ago
The main thing I would consider is that you want a sensor that actually measures CO2, which is usually an NDIR device. A lot of cheaper monitors and even some very fancy professional HVAC devices use “TVOC” meters and calculate a “CO2 equivalent”, and the performance of these devices is wildly variable. (The AirGradient devices are often configured with CO2 and separate SGP41 TVOC/NOx sensors. It’s entertaining to plot both raw TVOC and CO2 and to observe that they’re clearly showing similar diurnal variation, but the CO2 data is much cleaner.) Aside: the SGP41 data sheet doesn’t really recommend looking at the raw data, but you can. I have an esphome fork that does this.
mambo_giro 2y ago
I have a handful of these in my home and really appreciate the small form factor, long battery life, and options for accessing the data (on-screen live values via eInk display, encoded recent history displayed via QR code, or simple http server endpoint over wifi): https://github.com/davidkreidler/OpenCO2_Sensor https://github.com/davidkreidler/OpenCO2_Sensor. It was straightforward to integrate the accessories into my homebridge instance for ongoing monitoring and notifications as well. You can make one yourself from the information in the repository or buy one from the author at their Tindie storefront: https://www.tindie.com/products/davidkreidler/open-co2-sensor/ https://www.tindie.com/products/davidkreidler/open-co2-senso....
radicality 2y ago
I have a uHoo for a few years, and it’s still working fine, but the app is pretty bad and the device paywalls the raw data behind a subscription which always felt scammy to me. Also the refresh interval is 1min. So recently I went the diy route and pretty happy with a setup from m5stack: an SCD41 sensor plugged in to an AtomS3, running EspHome. I set the resolution to 5 seconds (can go down to 1 second), and then data goes to HomeAssistant -> InfluxDB and I plot it in Grafana. Cool to see the quick changes when using gas stove or opening up window. https://shop.m5stack.com/products/co2l-unit-with-temperature-and-humidity-sensor-scd41 https://shop.m5stack.com/products/co2l-unit-with-temperature... https://shop.m5stack.com/products/atoms3-dev-kit-w-0-85-inch-screen https://shop.m5stack.com/products/atoms3-dev-kit-w-0-85-inch...
kingsloi 2y ago
I have a https://www.birdie.design/en-us https://www.birdie.design/en-us (I think it was previously called a Canary) mounted in my living room, and it's a great lil device! Overly dramatic, fun, and easy to know whether air quality is good or bad - would recommend!
kkfx 2y ago
Honestly? I recommend a VMC. Simply because monitoring allow to let you know something you can already know enough from your feelings, a VMC allow to breathe more oxygenated air.
- danudey 2y ago
  It's still useful to know to what extent your air is unpleasant (especially if it degrades over a long period of time and you acclimatize) as well as seeing historical trends.
- nequo 2y ago
  I have search for "VMC" but I am not sure what you mean. Do you have an example of a VMC that you recommend?
  - kkfx 2y ago
    Where possible a double flux one, passive if you are in a mild climate, active (a small "inverted" heat pump) otherwise. VMCs are essentially one or two ventilators in a device designed to push and/or extract air from a closed space to the exterior. Simple flux generally extract, then since you do not vacuum a home external air enter the home from various passages, it's good to exchange air, but not much in energy consumption terms. The double flux suck air out of humid places like kitchens and bathrooms, push exterior air in rooms etc balancing the volumes, with a central point to exchange heat. The passive one is roughly simple, essentially air flux are divided by a set of passages and the dividers allow the heat to pass from the outgoing air to the incoming. They can't recover all the heat/freshness but they still help because you get let's say hot exterior air in summer that get cooled in the device by the outgoing interior air, the opposite in the winter, a small extras to dump condensation, some filters to protect the ventilator etc. The active one is a heat pump, like a minisplit, where the exterior side is in the outgoing flux and the interior side on the incoming, so in winter you pick heat from the outgoing air, witch is normally MUCH "hot" than the incoming, and in summer you push heat in the outgoing air witch is normally much "cooler" allow for a significant COP. In mild climate and insulated homes an active (also called thermodynamic) VMC suffice to ventilate, heat and cool the home, in less mild climate can be integrated with others appliances too heat/cool the home. Personally in the Alps I have an active one in a new (5 years) home and with ~10kWh/day suffice for most spring and autumn alone, integrate minisplit in summer and water-water heat pump in the winter. A passive double flux VMC can be just 1-2kWh/day but of course it can't regulate humidity and can heat/cool the home, just allow to waste much less heat/cool while exchanging air. They are normally present in cold climate home where insulation was a thing since decades, so we need to exchange air anyway, they start to appear in hotter and mild climate since many have started to realize that a home for cold climate works as well in hot climate, because insulation is the same, you only need to tune the thickness and choose elements to shield the Sun in summer/allow it to penetrate as much as possible in winter. The same overall design from the arctic to tropic.
ashish01 2y ago
I made two using scd41, esp32 and esphome. https://shop.m5stack.com/products/co2l-unit-with-temperature-and-humidity-sensor-scd41 https://shop.m5stack.com/products/co2l-unit-with-temperature...
sebazzz 2y ago
I have an Awair, which is generally good and has a locally accessible API. However, one dick move they did when they shut down (cloud) support for the old Awair, they shut down local API access too. Unfortunately, I was only aware of that after buying the Awair.
subtlemuffins 2y ago
Airgradient: https://www.airgradient.com https://www.airgradient.com
deleted 2y ago
[deleted]
leemck 2y ago
The AZ-0001 Co2 meter. Vendor of a CO2 meter with zero to 2000 ppm co2, 30 or 50 ppm accuracy, serial data output, humidity, and temperature. The meter appears on a big name cheap sales website for a little under $200. https://www.co2meter.com/collections/handheld/products/az-ha-portable-co2-temp-and-rh-meter https://www.co2meter.com/collections/handheld/products/az-ha... One problem with the yellow AZ-0001 CO2 meter is the meter has to be manually restarted if the 9 volt input DC power is interrupted. A second problem is the CO2 value is quite sensitive to my breath when the meter is running on the garage workbench. For outdoor readings the mechanical problem is to put the meter at least 8 feet away from passing humans and also have the meter accessible for restarting. The same vendor sells a hockey puck device which I have also used. I stopped using the hockey puck due to it's humidity measure device. That was about 4 years ago. https://lessco2essay.blogspot.com/2015/08/carbon-dioxide-meter-mapper-and-logger.html https://lessco2essay.blogspot.com/2015/08/carbon-dioxide-met... Contact me for a copy of my Python CO2 meter software. The output of the software is lines of unixtime, GPS position, CO2, humidity, and temperature. leemck at gmail dot com. My CO2 interest is in the global excess CO2 problem.
stefantalpalaru 2y ago
[dead]

48 points by nequo 2y ago

Those of you who have used CO2 monitors to track your air quality indoors, what product do you recommend?

taf2 2y ago

I had fun with this one https://www.adafruit.com/product/5187 https://www.adafruit.com/product/5187 I used a tiny pico and display to make a little clock/sensor

JSDevOps 2y ago

https://aranet.com/products/aranet4-home https://aranet.com/products/aranet4-home

aloisdg 2y ago
Second this one. I own it and it is great
packetlost 2y ago
Yeah, I have this one and it's fantastic
agwa 2y ago
These are great. I have two of them and access the readings over Bluetooth using some Python code: https://github.com/Anrijs/Aranet4-Python https://github.com/Anrijs/Aranet4-Python (there's also a mobile app which I've never used) The eink display is really nice and if you disable Bluetooth the battery seems to last forever. It's 40% off right now which makes me tempted to pick up a third!
- hipadev23 2y ago
  That 40% off is a bit misleading, more like 10% off, as you've been able to get them for ~$165 on Amazon forever.
- jdoss 2y ago
  This python code looks fantastic. Worked right out of the gate. Thanks! Also I was not aware of the Aranet Radiation sensor. There goes some of my fun budget towards picking one of these up.
  - throwaranay4933 2y ago
    Also there is a Go equivalent (https://pkg.go.dev/sbinet.org/x/aranet4 https://pkg.go.dev/sbinet.org/x/aranet4) which works well on Linux and https://github.com/ryansouza/aranet4-exporter-go https://github.com/ryansouza/aranet4-exporter-go can be used to export the data to prometheus.
zerojames 2y ago
The Aranet is wonderful. I have had mine (Aranet 4) running for at least a year on a single charge.
joeyagreco 2y ago
I've had mine for 3 years now and it's great. Highly recommend.
Mountain_Skies 2y ago
Looks like it got the Hug of Death. Amazon sells it so just search for Aranet4 if the manufacturer's site is still struggling.
EA-3167 2y ago
I have one of these and have had zero problems, it's easy to use and seemingly very accurate. Incredible battery life too.
blankx32 2y ago
Does the app require any clouds to work?
- agwa 2y ago
  No, for the home version the app just connects over Bluetooth. The protocol is documented and there are robust open source implementations such as https://github.com/Anrijs/Aranet4-Python https://github.com/Anrijs/Aranet4-Python
unsupp0rted 2y ago
I'd love to buy one, but it costs `undefined` USD and won't add to cart

mrsirduke 2y ago

I've been happy with the awair element[1] for years. It also measures PM2 and temp/humidity/voc. [1]: https://www.getawair.com/products/element https://www.getawair.com/products/element

huevosabio 2y ago
I was happy with my awair until it died after a mere year and a half from purchase. Now its just an expensive brick.
- ailurooo 2y ago
  yeah that was my experience as well : (

phinnaeus 2y ago

I picked up a pair (indoor+outdoor) of https://www.airgradient.com https://www.airgradient.com monitors a few months ago. Happy with them so far though I have not decided on their final positions.

tomek_ycomb 2y ago
Excellent information from the person(s?) running air gradient with regards to pm sensor tech and design. Blog posts, etc. Ranges of kits from pre assembled to solder-yourself, that HN might like. (I am happy with my unit I gave to a friend with a wood fire stove heated house, and built one from kit to save some $ another time.)
- ds_opseeker 2y ago
  I'll second air gradient. Founder is really cool and supportive. Tech works. I bought some boards from him a while back, ordered the parts of off alibaba, and had a working ESP32 setup in short order.
mtlynch 2y ago
I also own an indoor AirGradient, and I like supporting open-source, open hardware, but I've been pretty disappointed with the product. There were no instructions in the box, and I had to dig around a while until I found this PDF from three years ago.[0] I normally can figure out a gadget without reading instructions, but this wasn't self-explanatory, as there are no inputs on the device itself, and I had to figure out how to connect it to my WiFi. It's open-source, but there are no official instructions for re-flashing the device. I had to piece the process together from third-party blog posts. The code itself is pretty low quality. They use tons of globals that could trivially be local variables, and they throw away precision of floats by casting them to ints. I fixed a bunch of bugs in my fork[1] and started contributing them upstream, and the maintainer told me that they just did a giant rewrite, so I'd have to re-do all my changes.[2] I get that it happens, but I would have preferred they announce in the README that the code is deprecated and not to work on it until this rewrite is complete. I still think it's fine overall and I'd probably buy it again for other rooms in my house, but I hope they get their act together a bit more. [0] https://www.airgradient.com/documents/AirGradient%20Manual%2012APR2021.pdf https://www.airgradient.com/documents/AirGradient%20Manual%2... [1] https://github.com/mtlynch/airgradient-arduino https://github.com/mtlynch/airgradient-arduino [2] https://github.com/airgradienthq/arduino/pull/45 https://github.com/airgradienthq/arduino/pull/45

huseyinkeles 2y ago

If you want to go DIY route; I use MH-Z19 sensor along with an ESP-32 which has ESP-Home installed on it, works very well and I log the data on Home Assistant.

sschueller 2y ago

I really like the airthings view plus which also measures radon. https://www.airthings.com/en/view-plus https://www.airthings.com/en/view-plus

xnx 2y ago
Seconded. Nice app that has good historical views and easy export of all data.
azamba 2y ago
+1 Airthings as long as you don't need any customer support.
pawelduda 2y ago
Been running the wave plus for 2 years and can recommend
sliken 2y ago
They have a github if you want to use it with your own graphana without requiring any cloud access: https://github.com/Airthings https://github.com/Airthings I've got one per floor in a 3 floor house and all get to the BT -> wifi gateway reliably.

anfractuosity 2y ago

I've used a Sensirion SCD30 (NDIR) sensor attached to a Pi running Grafana, which can be connected to via a web browser.

shagie 2y ago

There's a couple things here and it depends on your needs. The word "track" suggests history. I've got a https://www.amazon.com/gp/product/B0861777SL https://www.amazon.com/gp/product/B0861777SL which does what it says on the box and works. I've got one in my WFH office and one in my bedroom. There are times when I've woken up from a restless sleep to see that at a higher number (especially in the winter when the house is a bit more closed up). Also the track where I can look at the history and see things "oh yea, last about 4h after I cooked dinner the CO2 went up a bit." However, that's only the standard sensor stuff (temp, humidity, CO2). If you've got amazon devices, I've got https://www.amazon.com/gp/product/B08W8KS8D3 https://www.amazon.com/gp/product/B08W8KS8D3 ( Amazon Smart Air Quality Monitor ) which sits in my kitchen because I'm interested in other things there too. I've had some https://milacares.com https://milacares.com air purifiers in the house. They work as air monitors and purifiers. I had some issues with them, but they worked for a good while. Consider if you want instant or historical data. Do you want other data too? What integrations do you have in the house with other home automation? How much DIY are you going to engage in?

whalesalad 2y ago

I have been using one of these for years and it is quite nice. https://www.hydrofarm.com/p/autopilot-desktop-co2-monitor-data-logger/apcem2 https://www.hydrofarm.com/p/autopilot-desktop-co2-monitor-da...

OutOfHere 2y ago
A simple setting needs to be configured in it to change the threshold for alerts from that of an indoor marijuana farm to a regular home :-)
- whalesalad 2y ago
  I'm at 1500ppm right now. Time to open all the windows and let the heat in :\
  - OutOfHere 2y ago
    If using an AC, it is okay to keep the AC running with the window slightly open. This slows down the CO2 buildup while preserving most of the cooling. I would never go over 770 ppm though. Also, the Energy Saver mode of an AC obviously results in a much worse indoor CO2 level.

hedora 2y ago

If you don't want to go the DIY route, and also are interested in a weather station, Ambient Weather is great. It just works out of the box (the CO2 sensor is an add on), and supports a large pile of local APIs and cloud service integrations. We went with one of the fancier models, including a nice LCD display and a solid state (ultrasonic) wind monitor, since we get hurricane-level gusts around here. It's held up fine so far. One annoyance: At least the last time I checked, all the sensors have to be in radio range of the base station. It'd be nice if they had WiFi bridges so we could monitor multiple buildings, etc, with one system.

AtlasBarfed 2y ago
The sad reality of consumer IoT is that you will diy eventually. If you start out with a magically integrated system, well, just wait a few years. Hope you thoroughly document your house for its next owner!

mrweasel 2y ago

I've been looking at the Eve Room, but haven't gotten it yet. It's one of the only devices I found that seems to work with HomeKit.

danudey 2y ago
I have an Eve Room and I quite like it. The little e-ink display is incredibly easy to read in most lighting conditions (i.e. any condition where there's some light), and the battery life is really fantastic. I also have an air monitor from Qingping[0] which I got from Amazon, and I quite like that as well. Instead of VOCs, it reports pm2.5 and pm10 particulate, which was important for us (in Vancouver) because of the advent of 'wildfire season' in the past few years. I think I would prefer to have the pm2.5/pm10 sensors in the living room and bedrooms (which have windows and where people spent the most time) and the VOC sensors in the kitchen (where cooking/burning happens) and bathroom (where cleaning products are used but ventilation is poor) but I haven't gotten around to buying more of everything yet. [0] https://www.amazon.ca/gp/product/B092HK4BB1/ https://www.amazon.ca/gp/product/B092HK4BB1/

sofixa 2y ago

I have Apollo Automation MSR-1 (it does multiple things, including CO2 and mmWave movement/presence detection; they also have AIR-1 which tracks all sorts of air quality metrics such as VOC etc), flashed with ESPHome reporting to my Home Assistant setup. It's main advantage is that it's extremely affordable compared to the competition, and entirely local. Also I have a Netatmo Indoor Air Quality Monitor (requires their cloud service to work, but there's a Home Assistant integration too) which, alongside PM2.5 and CO2, also does sound and alerts me when music/etc. is too loud.

radicality 2y ago
That looks like a nice all-in-one. If anyone from Apollo Automation reading it, perhaps you could also offer a version with the improved scd41 sensor vs the scd40.

londons_explore 2y ago

MH-Z19 module and a WiFi Arduino (esp32) which dumps co2 and temperature into Prometheus. It's like 20 lines of code and very rewarding to write.

crazygringo 2y ago

If you want something that looks attractive in your room and has an app to view history (so the opposite of "hacker"), I highly recommend Awair, been using it for years: https://www.getawair.com/products/element https://www.getawair.com/products/element You can configure the device display to just show numerical CO2 (that's what I do). Seeing the CO2 history graphed on your phone might not seem like it's all that necessary, but I find it really is -- you can see how it falls when you're out, you can see how quickly it skyrockets when you turn on the oven, you can see how long it takes to settle into a steady state overnight. Seeing CO2 over time gives me a conceptual understanding of what's actually happening, which I didn't have with my previous CO2 monitor that just showed the current value.

zeke_the_cat 2y ago

The GQ Electronics GMC-520 has been very reliable for me. It has a Geiger counter and other functionality also.

blankx32 2y ago

Some good input on this thread such as that from brendangregg - https://news.ycombinator.com/item?id=34648021 https://news.ycombinator.com/item?id=34648021

licebmi__at__ 2y ago

Genuinely curious, what are the advantages of a CO2 monitor? I mean, I get you can “track air quality” but what exactly does that mean on day to day basis?

crazygringo 2y ago
It means you know when to open the windows more to maintain fresh air. I think much better and am in a better mood when CO2 levels are lower, or when air is fresher generally (the two generally correlate). But I don't want to keep my windows wide open all the time because that wastes AC or heat. So if the monitor is reading above 650, I open windows a little bit. If it's reading over 800, I open them wider. If it's under 550, I'll go back to closing them. It's just a few times a day, but it really helps. And it's not something I can "tell" otherwise easily, because if I have brain fog or am in a bad mood then high CO2 is just one of many possible reasons -- is my blood sugar low? Did I get enough sleep? Etc. A CO2 monitor feels just as essential to my health as weighing myself every day, no bright or blue lights two hours before bed, not overeating carbs, and so forth. It really helps with my overall alertness and productivity in a major way.
- moooo99 2y ago
  I‘m genuinely curious, but isn’t a CO2 sensor an unnecessary high tech solution considering you could just open your window once a day for a few minutes and let the air exchange?
zefhous 2y ago
DHH gave a talk about this a while ago with good citations to studies about CO2 concentration and other VOCs. https://www.youtube.com/watch?v=MRqh8oLY7Ik https://www.youtube.com/watch?v=MRqh8oLY7Ik

amluto 2y ago

The main thing I would consider is that you want a sensor that actually measures CO2, which is usually an NDIR device. A lot of cheaper monitors and even some very fancy professional HVAC devices use “TVOC” meters and calculate a “CO2 equivalent”, and the performance of these devices is wildly variable. (The AirGradient devices are often configured with CO2 and separate SGP41 TVOC/NOx sensors. It’s entertaining to plot both raw TVOC and CO2 and to observe that they’re clearly showing similar diurnal variation, but the CO2 data is much cleaner.) Aside: the SGP41 data sheet doesn’t really recommend looking at the raw data, but you can. I have an esphome fork that does this.

mambo_giro 2y ago

I have a handful of these in my home and really appreciate the small form factor, long battery life, and options for accessing the data (on-screen live values via eInk display, encoded recent history displayed via QR code, or simple http server endpoint over wifi): https://github.com/davidkreidler/OpenCO2_Sensor https://github.com/davidkreidler/OpenCO2_Sensor. It was straightforward to integrate the accessories into my homebridge instance for ongoing monitoring and notifications as well. You can make one yourself from the information in the repository or buy one from the author at their Tindie storefront: https://www.tindie.com/products/davidkreidler/open-co2-sensor/ https://www.tindie.com/products/davidkreidler/open-co2-senso....

radicality 2y ago

I have a uHoo for a few years, and it’s still working fine, but the app is pretty bad and the device paywalls the raw data behind a subscription which always felt scammy to me. Also the refresh interval is 1min. So recently I went the diy route and pretty happy with a setup from m5stack: an SCD41 sensor plugged in to an AtomS3, running EspHome. I set the resolution to 5 seconds (can go down to 1 second), and then data goes to HomeAssistant -> InfluxDB and I plot it in Grafana. Cool to see the quick changes when using gas stove or opening up window. https://shop.m5stack.com/products/co2l-unit-with-temperature-and-humidity-sensor-scd41 https://shop.m5stack.com/products/co2l-unit-with-temperature... https://shop.m5stack.com/products/atoms3-dev-kit-w-0-85-inch-screen https://shop.m5stack.com/products/atoms3-dev-kit-w-0-85-inch...

kingsloi 2y ago

I have a https://www.birdie.design/en-us https://www.birdie.design/en-us (I think it was previously called a Canary) mounted in my living room, and it's a great lil device! Overly dramatic, fun, and easy to know whether air quality is good or bad - would recommend!

kkfx 2y ago

Honestly? I recommend a VMC. Simply because monitoring allow to let you know something you can already know enough from your feelings, a VMC allow to breathe more oxygenated air.

danudey 2y ago
It's still useful to know to what extent your air is unpleasant (especially if it degrades over a long period of time and you acclimatize) as well as seeing historical trends.
nequo 2y ago
I have search for "VMC" but I am not sure what you mean. Do you have an example of a VMC that you recommend?
- kkfx 2y ago
  Where possible a double flux one, passive if you are in a mild climate, active (a small "inverted" heat pump) otherwise. VMCs are essentially one or two ventilators in a device designed to push and/or extract air from a closed space to the exterior. Simple flux generally extract, then since you do not vacuum a home external air enter the home from various passages, it's good to exchange air, but not much in energy consumption terms. The double flux suck air out of humid places like kitchens and bathrooms, push exterior air in rooms etc balancing the volumes, with a central point to exchange heat. The passive one is roughly simple, essentially air flux are divided by a set of passages and the dividers allow the heat to pass from the outgoing air to the incoming. They can't recover all the heat/freshness but they still help because you get let's say hot exterior air in summer that get cooled in the device by the outgoing interior air, the opposite in the winter, a small extras to dump condensation, some filters to protect the ventilator etc. The active one is a heat pump, like a minisplit, where the exterior side is in the outgoing flux and the interior side on the incoming, so in winter you pick heat from the outgoing air, witch is normally MUCH "hot" than the incoming, and in summer you push heat in the outgoing air witch is normally much "cooler" allow for a significant COP. In mild climate and insulated homes an active (also called thermodynamic) VMC suffice to ventilate, heat and cool the home, in less mild climate can be integrated with others appliances too heat/cool the home. Personally in the Alps I have an active one in a new (5 years) home and with ~10kWh/day suffice for most spring and autumn alone, integrate minisplit in summer and water-water heat pump in the winter. A passive double flux VMC can be just 1-2kWh/day but of course it can't regulate humidity and can heat/cool the home, just allow to waste much less heat/cool while exchanging air. They are normally present in cold climate home where insulation was a thing since decades, so we need to exchange air anyway, they start to appear in hotter and mild climate since many have started to realize that a home for cold climate works as well in hot climate, because insulation is the same, you only need to tune the thickness and choose elements to shield the Sun in summer/allow it to penetrate as much as possible in winter. The same overall design from the arctic to tropic.

ashish01 2y ago

I made two using scd41, esp32 and esphome. https://shop.m5stack.com/products/co2l-unit-with-temperature-and-humidity-sensor-scd41 https://shop.m5stack.com/products/co2l-unit-with-temperature...

sebazzz 2y ago

I have an Awair, which is generally good and has a locally accessible API. However, one dick move they did when they shut down (cloud) support for the old Awair, they shut down local API access too. Unfortunately, I was only aware of that after buying the Awair.

subtlemuffins 2y ago

Airgradient: https://www.airgradient.com https://www.airgradient.com

deleted 2y ago

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leemck 2y ago

The AZ-0001 Co2 meter. Vendor of a CO2 meter with zero to 2000 ppm co2, 30 or 50 ppm accuracy, serial data output, humidity, and temperature. The meter appears on a big name cheap sales website for a little under $200. https://www.co2meter.com/collections/handheld/products/az-ha-portable-co2-temp-and-rh-meter https://www.co2meter.com/collections/handheld/products/az-ha... One problem with the yellow AZ-0001 CO2 meter is the meter has to be manually restarted if the 9 volt input DC power is interrupted. A second problem is the CO2 value is quite sensitive to my breath when the meter is running on the garage workbench. For outdoor readings the mechanical problem is to put the meter at least 8 feet away from passing humans and also have the meter accessible for restarting. The same vendor sells a hockey puck device which I have also used. I stopped using the hockey puck due to it's humidity measure device. That was about 4 years ago. https://lessco2essay.blogspot.com/2015/08/carbon-dioxide-meter-mapper-and-logger.html https://lessco2essay.blogspot.com/2015/08/carbon-dioxide-met... Contact me for a copy of my Python CO2 meter software. The output of the software is lines of unixtime, GPS position, CO2, humidity, and temperature. leemck at gmail dot com. My CO2 interest is in the global excess CO2 problem.

stefantalpalaru 2y ago

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