I was monitoring indoor CO2 at my home. It definitely swings in the 800-1000 range, especially if I keep the door to the rest of the house closed or mostly clo

I was monitoring indoor CO2 at my home. It definitely swings in the 800-1000 range, especially if I keep the door to the rest of the house closed or mostly closed. But if I leave that door open, it often drops to 600 or less during the day when I'm probably not adding to the CO2. If I open a window it drops to about 430 in a few minutes. It's noisy where I live, though, so I mostly don't ventilate much externally now and live with it.