CO2 Sensors for home

What country are you in? The device selection does vary.

It looks like Awair now has an official integration through the new V3 app, So I would start with that.:sunglasses:

You can also get a partial integration with anything with Ifttt.

In addition, there is a netatmo integration which is pretty popular, but does require custom code. Those devices are available in both the US and the UK.

Help locating CO2 Air Quality sensor