You can't see it, smell it or taste it! Carbon monoxide (CO) is stealthily deadly! Even furry friends like cats and dogs are not able to detect carbon monoxide gas because it has no scent (it's odorless), colorless, and doesn't cause irritation to the eyes or body, which is why a CO device like the Netatmo CO alarm is so vital.

The Netatmo carbon monoxide alarm measures 10cm in diameter and 2.5cm thick and weighs just 146 grams so, it's about the same footprint as a smoke detector. The Netatmo carbon monoxide alarm does not detect smoke - only CO gas - and uses an electrochemical reaction via a gel to detect CO toxic gas. When carbon monoxide is present, the gel changes color, triggering the alarm. Some carbon monoxide detectors use other methods to detect CO by sensing changes in electrical current and electrical resistance using silica chips.


The Netatmo CO alarm makes a loud 85dB noise that can be heard at 3 meters (~120 inches) distance. The alarm only gets triggered when a specific carbon monoxide ppm level is present for a certain time. The Netatmo CO alarm sounds at three different CO ppm exposure intervals: 50ppm (after 60-90 minutes of continuous exposure), 100ppm (after 10-40 minutes of exposure and 300ppm (after 3 minutes of carbon monoxide exposure). Because there has to be a continuous exposure for the alarm trigger, it eliminates possible false alarms, which would defeat the purpose. 

 

That said, the alarm still reports (via the app) when it detects lower levels of CO ppm (e.g. 2ppm), which is useful. The Netatmo carbon monoxide alarm is battery-powered, although you can also get them as a wall socket plug-in device and hardwired, which have the advantage of constant power. That said, carbon monoxide is thinner than the air, making the Netatmo CO alarm more advantageous because you can place it higher up than a plug socket and also relocate it anywhere at any location (e.g. garage or outdoor annex).



There are two non-replaceable 3V lithium (coin cell) batteries installed inside the Netatmo carbon monoxide alarm, which have a 10-year runtime. This is also the life cycle of the CO gel sensor, which means the Netatmo CO alarm has to be replaced after 10 years. A few weeks before the battery runs out, you will see a flashing orange light and will hear a series of beeps every couple of minutes. By default, the Netatmo carbon monoxide alarm will make a sound and pop up a notification on your phone's screen (in real time) when it detects any abnormal level of carbon monoxide. The notification sound and popup message can be disabled via the Netatmo's Home+Security mobile app. The app allows you to install an unlimited amount of Netatmos carbon monoxide alarms.


Other than having to sign up for an account, the Netatmo Home+Security app is free to download and free to use with no in-app fees. Pairing the CO alarm to the app is easy, thanks to the easy to follow on-screen instructions. Pairing connecting is done via 2.4Ghz Wifi (not bluetooth) so, you will need an Internet router in order to use this device. The Netatmo CO alarm system monitors the Wifi connection signal too and will let you know if there are any issues. A few other things you can do from the app include changing alert rules, alarm sound test reminder (monthly, fortnight, biannually or annually) and alarm test.


The Netatmo carbon monoxide alarm is a closed system sandwiched between two plastic enclosures that keep the circuitry and electronics isolated from the outside. The enclosure is not completely sealed though. There is a grey metal grille mesh (for ventilation), as well as a small tab lid on the rear side of the enclosure concealing a tiny switch and a blue reset button, which you only have to use when pairing the CO alarm to a different phone.


The tab lid locks and unlocks via a twisting motion. To unlock the tab lid, simply twist the lid anticlockwise and viceversa. The tab lid also integrates two small hole openings to wall mount the Netatmo carbon monoxide alarm up on a wall (two black metal screws ( and two plastic wall plugs are included). The Netatmo CO alarm device has a very simple user friendly design. It has three status leds (on the top edge) and one physical button on the front of the unit to mute the alarm when it sounds.


The button is completely leveled so, it doesn't protrude or stick out. The Netatmo carbon monoxide alarm system has been designed to self-monitor itself and report back to the user (via notification alerts) when it encounters or detects any issues with the monoxide alarm system. Aside from having to dust off the device regularly, the Netatmo carbon monoxide alarm doesn't require any other maintance. It is silent in operation so, you won't even know it's there other than when the green led flashes every 60 seconds to indicate it is working.


If you have any gas-powered or propane-powered appliance (e.g. boiler central heating, fireplace), a CO alarm is even more important than a smoke alarm because CO is a silent killer that needs to be watched closely - especially with poor ventilation. When the fuel burning equipment becomes faulty, it can start leaking carbon monoxide gas. Some tell tale signs of a carbon monoxide leak are sooty stains, smoky stale smell and unexplained headache/dizziness. The reason carbon monoxide gas is deadly is because once inhaled it takes a long time for the body to eliminate carbon monoxide (about 24 hours). Carbon monoxide becomes life threatening after 3 hours of exposure at 400 PPM and deadly after 1 hour of exposure at 1600ppm.


A good safe guard against carbon monoxide poisoning, it's proper ventilation. Keeping windows regularly open (when possible) will help reduce carbon monoxide build-up. The Netatmo CO alarm is a standalone carbon monoxide device, which is better because a CO/Smoke alarm combo can get confusing. The Netatmo CO alarm can also operate in hot and freezing (-10 °C to +40 °C) weather conditions, making it suitable for places such as a garage or outdoor shed. It comes with the NF mark (french), CE marking (european) and UKCA (UK) certification, which means the the Netatmo carbon monoxide alarm has been tested by independent bodies. You can buy the Netatmo Carbon Monoxide Alarm from amazon. Check out thge review of the Netatmo weather station homekit.