I run a CO2 monitor to let me know when to open the windows in the winter cause it's damn cold here but yeah: many Americans never open any windows. Usually th

I run a CO2 monitor to let me know when to open the windows in the winter cause it's damn cold here but yeah: many Americans never open any windows. Usually the houses are too poorly sealed to keep the air in anyways, so you get slow air replacement from the leaks.