[matheweis]

I’m not surprised by this at all. I purchased a pro-sumer grade (Ambient Weather) weather station a couple of years ago that happened to include an indoor CO2 sensor. Among other things I discovered:

* Modern building codes (for energy efficiency?) leave buildings far too sealed. HRV/ERV should probably be mandatory as we continue to have tighter regulations for insulating homes.

* The level of CO2 produced by a Gas stove range is a bit shocking.

I now leave my windows open a crack during the winter which keeps CO2 levels around 800-1200ppm. If I purchased a home I’d upgrade the HVAC system to include an HRV/ERV.