# Air Quality / CO2: what is it exactly and which sensor to buy **URL:** \ **Category:** Devices\ **Created:** [February 22, 2021, 8:31am UTC](https://community.homey.app/t/air-quality-co2-what-is-it-exactly-and-which-sensor-to-buy/43452 "2021-02-22T08:31:47Z")\ **Posts on this page:** 19\ **Page:** 1
**Author:** ![anon61197305](https://avatars.discourse-cdn.com/v4/letter/a/8baadc/32.png) [@anon61197305](https://community.homey.app/u/anon61197305)\ **Post date:** [February 22, 2021, 8:31am UTC](https://community.homey.app/t/air-quality-co2-what-is-it-exactly-and-which-sensor-to-buy/43452/1 "2021-02-22T08:31:47Z")
I am a bit confused about air quality and CO2 sensors. First off all: what is is and where is it measured in? My Withings Scale and Netatmo Weatherstation measure CO2 in PPM. Which is quite straightforward. I have also a Dyson. Which reports the outside quality (AQI) in a scale from 1 to 11. And measures the inside quality (particles and VOS (= Dutch; Vluchtige Organische Stoffen) in a scale without any numbers (it uses good, average, bad, very bad). What is Dyson really measuring? Second: I want 2 sensors to measure quality I really like 2 CO2 sensors, to measure the home office and bedroom for CO2. While working from home, I noticed that the living room CO2 is peaking. I want to monitor those rooms too. Are there any good sensors? Or is an extra inside module for Netatmo the better option? Also, are there sensors that also measure what my Dyson measures? Or is that not good information to know (other for Dyson to sell their air cleaners)? Can anybody help or explain? šŸ™‚ ---
**Author:** ![Toon\_Vos](https://avatars.discourse-cdn.com/v4/letter/t/57b2e6/32.png) [@Toon\_Vos](https://community.homey.app/u/Toon_Vos)\ **Post date:** [February 22, 2021, 9:13am UTC](https://community.homey.app/t/air-quality-co2-what-is-it-exactly-and-which-sensor-to-buy/43452/2 "2021-02-22T09:13:29Z")
CO2 is an indication for air quality / level of ventilation I use the Netatmo sensors as you mention and have those connected to Homey. Every morning if CO2 levels went over 1000 it sends me a warning. In optimal situation it would trigger a process which would open a window or increase ventilation. ---
**Author:** ![rindler](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/rindler/32/5501_2.png) [@rindler](https://community.homey.app/u/rindler)\ **Post date:** [February 22, 2021, 9:16am UTC](https://community.homey.app/t/air-quality-co2-what-is-it-exactly-and-which-sensor-to-buy/43452/3 "2021-02-22T09:16:34Z")
You could buy the Netatmo healthy home coach if you want more plug and play CO2-sensors. PM2.5/PM10-sensors reacts to particles in the air, like dust, smoke, pollen and so on. VOC-sensors also reacts to human breathe but also to general ā€œbad smellā€, paint and so on. And sometimes itā€™s a bit to hard why the value is increased. Often the value is calculated to some index instead of ppm where low value is the best air quality the sensor has measured and a high value is the worst. The sensors often self calibrate so itā€™s not possible to compare those values between different homes but they are good to measure the change in air quality in a specific location. ---
**Author:** ![rindler](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/rindler/32/5501_2.png) [@rindler](https://community.homey.app/u/rindler)\ **Post date:** [February 22, 2021, 9:42am UTC](https://community.homey.app/t/air-quality-co2-what-is-it-exactly-and-which-sensor-to-buy/43452/4 "2021-02-22T09:42:32Z")
![Screenshot_20210222-104036_Chrome](https://us1.discourse-cdn.com/flex025/uploads/athom/original/3X/6/9/697d81b3fe0d29ffd1f7c95b796f7d7e63afbfed.jpeg) Insights from one of my arduino air quality sensors, measuring CO2, VOC and PM2.5. ---
**Author:** ![Martijn\_C](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/martijn_c/32/39993_2.png) [@Martijn\_C](https://community.homey.app/u/Martijn_C)\ **Post date:** [February 22, 2021, 9:43am UTC](https://community.homey.app/t/air-quality-co2-what-is-it-exactly-and-which-sensor-to-buy/43452/5 "2021-02-22T09:43:23Z")
MCO Home CO2. Works perfectly and accurately. ---
**Author:** ![anon61197305](https://avatars.discourse-cdn.com/v4/letter/a/8baadc/32.png) [@anon61197305](https://community.homey.app/u/anon61197305)\ **Post date:** [February 22, 2021, 10:12am UTC](https://community.homey.app/t/air-quality-co2-what-is-it-exactly-and-which-sensor-to-buy/43452/6 "2021-02-22T10:12:24Z")
Thanks! @Toon_Vos you have an excellent last name for this topic! šŸ™‚ @Martijn_C for that price I think I add just a Netatmo module to my system. @rindler, the Home Coach is, unfortunately, a different Netatmo product (and does roughly the same as the Weather Station). I think Arduino projects are not really for me. I had hoped there was a bit of an affordable sensor. ---
**Author:** ![Martijn\_C](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/martijn_c/32/39993_2.png) [@Martijn\_C](https://community.homey.app/u/Martijn_C)\ **Post date:** [February 22, 2021, 10:13am UTC](https://community.homey.app/t/air-quality-co2-what-is-it-exactly-and-which-sensor-to-buy/43452/7 "2021-02-22T10:13:41Z")
Sure, but in my opinion the quality is better and youā€™re not relying on WiFi/APIā€™s. Direct integration. ---
**Author:** ![rindler](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/rindler/32/5501_2.png) [@rindler](https://community.homey.app/u/rindler)\ **Post date:** [February 22, 2021, 10:15am UTC](https://community.homey.app/t/air-quality-co2-what-is-it-exactly-and-which-sensor-to-buy/43452/8 "2021-02-22T10:15:01Z")
Just thought itā€™s not possible to add another netatmo indoor module? That was why I suggested the home coach. ---
**Author:** ![anon61197305](https://avatars.discourse-cdn.com/v4/letter/a/8baadc/32.png) [@anon61197305](https://community.homey.app/u/anon61197305)\ **Post date:** [February 22, 2021, 10:19am UTC](https://community.homey.app/t/air-quality-co2-what-is-it-exactly-and-which-sensor-to-buy/43452/9 "2021-02-22T10:19:08Z")
That is stating the obvious indeed. But to be honest I am not looking for that level of quality I guess. I do agree that locking in into a third party service is always the second best option, but putting everything in the balance: for ā…“ of that price I am happy with it. But thanks! šŸ™‚ @rindler I believe you can add up to 2 extra modules to the weather station, adding it up to a total of three (plus one outside module). ---
**Author:** ![rindler](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/rindler/32/5501_2.png) [@rindler](https://community.homey.app/u/rindler)\ **Post date:** [February 22, 2021, 10:28am UTC](https://community.homey.app/t/air-quality-co2-what-is-it-exactly-and-which-sensor-to-buy/43452/10 "2021-02-22T10:28:52Z")
Ah, seems right. Then I think itā€™s the best choice except that you donā€™t get any values when the netatmo cloud is down, hehe. Happened me once for a couple of days, but other than that I think the values are about right for that price. ---
**Author:** ![Arnold\_vd\_Linden](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/arnold_vd_linden/32/19336_2.png) [@Arnold\_vd\_Linden](https://community.homey.app/u/Arnold_vd_Linden)\ **Post date:** [February 22, 2021, 12:11pm UTC](https://community.homey.app/t/air-quality-co2-what-is-it-exactly-and-which-sensor-to-buy/43452/11 "2021-02-22T12:11:56Z")
I have build one this weekend based on a Wemos mini and the SGP30 shield for around ā‚¬18. It measures TVOC and eCO2. ![image](https://us1.discourse-cdn.com/flex025/uploads/athom/original/3X/4/4/44c7eaeb9b6c8bc9d4fe1d5bdd78b508eda9ff33.jpeg) It uses my MQTT server to connect with Homey using the [Tasmota MQTT](https://homey.app/nl-nl/app/com.paveld.tasmota/Tasmota-MQTT/) app. Installing Tasmota on the Wemos is pretty easy and well documented on the wiki pages. I donā€™t know how accurate the measurements are because of the use of eCO2. But for my purpose I think it will work. ---
**Author:** ![matrover](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/matrover/32/12112_2.png) [@matrover](https://community.homey.app/u/matrover)\ **Post date:** [February 22, 2021, 2:11pm UTC](https://community.homey.app/t/air-quality-co2-what-is-it-exactly-and-which-sensor-to-buy/43452/12 "2021-02-22T14:11:10Z")
iā€™m using the Awair sensors, which have more than only co2. really like those and have direct integration. ---
**Author:** ![TonyaDigital](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/tonyadigital/32/36776_2.png) [@TonyaDigital](https://community.homey.app/u/TonyaDigital)\ **Post date:** [March 15, 2021, 6:04pm UTC](https://community.homey.app/t/air-quality-co2-what-is-it-exactly-and-which-sensor-to-buy/43452/13 "2021-03-15T18:04:50Z")
![Screenshot_20210315-190241_Homey](https://us1.discourse-cdn.com/flex025/uploads/athom/original/3X/b/5/b5f13570d8f26759a33301d20ae3ea5df88aa2f0.jpeg) Iā€™m using a Norwegian designed air quality monitor that works perfectly with Homey, called AirThings. Hereā€™s a screenshot from within the Homey app, as you can see it covers most of the data you need. ---
**Author:** ![Automansion](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/automansion/32/45899_2.png) [@Automansion](https://community.homey.app/u/Automansion)\ **Post date:** [October 13, 2021, 7:00pm UTC](https://community.homey.app/t/air-quality-co2-what-is-it-exactly-and-which-sensor-to-buy/43452/14 "2021-10-13T19:00:03Z")
@TonyaDigital Hi, Iā€™m looking for Airthings users, hope you can answer. Youā€™re using a Wave Plus? Hub or direct to Homey? The official app at [Airthings BLE (deprecated) App for Homey | Homey](https://homey.app/en-gb/app/com.airthings/Airthings/) or something else? That page shows no flow cards for radon or VOC, has that been fixed? Also, have you heard any news of Airthings View Plus support? Itā€™s not listed as supported in Homey yet. thanks ---
**Author:** ![Gruijter](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/gruijter/32/1973_2.png) [@Gruijter](https://community.homey.app/u/Gruijter)\ **Post date:** [October 13, 2021, 7:06pm UTC](https://community.homey.app/t/air-quality-co2-what-is-it-exactly-and-which-sensor-to-buy/43452/15 "2021-10-13T19:06:47Z")
Just wanted to let you all know of a new app I published a few days ago. It supports the airQ device. Not a cheap device, but it has many built in air quality sensors, including a real CO2 sensor. A lot of other devices use some other sensor to approximate CO2. > [@\[APP\]\[PRO\] airQ advanced indoor Air Quality meter](https://community.homey.app/t/52938): > > airQ airQ provides advanced indoor air quality data Supported sensor data (depending on the airQ version): Temperature Humidity % Humidity absolute Air pressure Noise Noise Maximum tVOC SO2 CO NO2 O3 O2 CO2 PM1 PM2.5 PM10 Furthermore the following information is supported: Health index Performance index Virus Free index Dew point Health alarm Virus alarm Performance alarm Fire alarm Gas alarm The following controls are possible from Homey: Sound beeper with duration,ā€¦ ---
**Author:** ![Marcel\_Visser](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/marcel_visser/32/66024_2.png) [@Marcel\_Visser](https://community.homey.app/u/Marcel_Visser)\ **Post date:** [November 3, 2021, 8:12pm UTC](https://community.homey.app/t/air-quality-co2-what-is-it-exactly-and-which-sensor-to-buy/43452/16 "2021-11-03T20:12:33Z")
Hi guys, Are there also some cheaper alternatives from xiaomi/aqara by example that are compatible with Homey? I cannot find any cheap solutionsā€¦ However, the measurements need to be reliable, so Iā€™m not sure if a cheap sensor wil do that the right wayā€¦ other people here any experience with some cheaper co2 sensors? ---
**Author:** ![Henk\_Renting](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/henk_renting/32/87634_2.png) [@Henk\_Renting](https://community.homey.app/u/Henk_Renting)\ **Post date:** [November 3, 2021, 8:46pm UTC](https://community.homey.app/t/air-quality-co2-what-is-it-exactly-and-which-sensor-to-buy/43452/17 "2021-11-03T20:46:49Z")
Aqara only has TVOC sensors that can be connected to Homey as far as I knowā€¦ > **[Xiaomi Aqara TVOC Sensor - XiaomiProducts](https://www.xiaomiproducts.nl/nl/xiaomi-aqara-tvoc-sensor.html)** > > De Xiaomi Aqara TVOC Sensor detecteert schadelijke VOC's, temperatuur en luchtvochtigheid. Af te lezen op mooi scherm en integratie met HomeKit. Bestel ā€˜m nu! ---
**Author:** ![Marcel\_Visser](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/marcel_visser/32/66024_2.png) [@Marcel\_Visser](https://community.homey.app/u/Marcel_Visser)\ **Post date:** [November 4, 2021, 7:20am UTC](https://community.homey.app/t/air-quality-co2-what-is-it-exactly-and-which-sensor-to-buy/43452/18 "2021-11-04T07:20:14Z")
Dankje! Die was ik wel tegen gekomen iddā€¦ Maar, meet die wel co2? Dat lees ik nergensā€¦ ---
**Author:** ![Henk\_Renting](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/henk_renting/32/87634_2.png) [@Henk\_Renting](https://community.homey.app/u/Henk_Renting)\ **Post date:** [November 4, 2021, 7:40am UTC](https://community.homey.app/t/air-quality-co2-what-is-it-exactly-and-which-sensor-to-buy/43452/19 "2021-11-04T07:40:02Z")
Nope, it is a TVOC sensor. So it also measures air quality, but no CO. (english forum part here)