[dilippkumar]

I have an Airthings Wave. It does CO2 along with a couple of other things.

I really like mine. It helped me discover that I was sensitive to volatile organic compounds: every time I felt the air was stuffy inside my apartment, it corresponded to a VOC peak that was happening right then.

The one downside to the Airthings Wave is that it looks like hospital equipment. Grey, lifeless plastic pill design that was probably outdated even in the 1970s.

If you ignore how it looks, it works fantastic.

[sliken]

Love mine. I think it looks fine, has a simple display to display a few values, white, and nicely rounded. Basically invisible. I use it to collect the info so I can look at the graphs as needed.

Seems like a really nice design. I was impressed that bluetooth LE was enough to connect reliably across 3 floors (with the gateway on the middle floor) of my house. The view plus automatically acts as a hub if you plug in USB for power, but falls back to batteries as needed.

All in all just about perfect, it works, easy to setup, and collects tons of data (Radon, PM2.5, CO2, Humidity, Temp, VOC, and pressure). I do wish it collected carbon monoxide though.

[cypherpunks01]

I'd second the Airthings device, they have pretty high quality sensors and include VOCs, CO2, pm2.5, radon, and a few others. A little bit pricey is the only downside for me.

[xnx]

Love my Airthings Wave. It works exactly as advertised and is very easy to export all the readings as CSV.

[xyzelement]

Just another vote for it - love it.