I use an Awair, also in a cold climate. Seeing the data for my air quality motivated me to install an air exchanger. Having the monitor allowed me to see how much we needed to exchange in order to keep the CO2 at a decent level.

For anyone with a modern home that is sealed up average or better, an air monitor indoors is almost a must.

On the topic of the number of people and CO2, I'm tempted to have it alert me when I'm out of town and the CO2 rises. I have an alarm, but who would think to defeat the innocent looking air monitor on the shelf?