Low level carbon monoxide monitoring

I have been on the hunt for a low level carbon monoxide monitor that ideally integrates with Home Assistant. There’s a lot of good evidence that highlights why it’s important to monitor and alert CO even at low amounts. Here’s a good summary:

Here are some standalone units that I have found:

Are you aware of anything that would integrate with HA?

This is actually a topic I’m not very familiar with, as I haven’t tried many low-level CO monitors. From the ones I have tried, I’ve found sensitivity, accuracy, and cross-sensitivity to be large issues. However, the first monitor you shared seems to perform quite well in this regard (±5% accuracy and less cross-sensitivity than I see with other monitors).

Of course, there are air quality monitors with CO sensors within, but I haven’t found a CO sensor in one of these monitors yet that I would trust. I will research this further and see if I can find any further information!

Would you consider making your own? This could also be an option, and there seem to be a few tutorials online for making one that would integrate with HA.

I was excited that the Apollo AIR-1 had a gas sensor to monitor CO2. However, I was disappointed to read in your review that it wasn’t that great at measuring those gasses.

I’m not opposed to making my own, especially if a quality sensor could be found. I would prefer something from a trustworthy commercial source as they likely have implemented additional algorithms to improve the output.

I have looked to see if I could find sensor information for the commercial monitors. Most just mentioned using an “Electromechanical” sensor. The Defender listed theirs as Figaro TGS 5042.

I agree, as I’ve wanted a good CO sensor in low-cost air quality monitors for a while. However, I think that particular sensor has more issues than advantages.

Interesting on the Figaro sensor. The Amazon Smart Air Quality Monitor also uses one of those, and it seems to be an okay sensor, but it doesn’t have fantastic accuracy. If you just want a general indication as to the CO levels, it could be worth looking into (not the Amazon monitor, but the Defender).