Just a note that our CO2 detector was mounted on the high part of the wall... Last time I checked CO2 is heavier than air. Looks like I'd be dead before that would go off. Please check your setup and be safe.
Although you are correct that CO2 is heavier than air and is relatively harmless. CO, carbon monoxide, is deadly and is slightly lighter than air and will rise. CO detectors are mounted high.
OK, first of all it is a CO (Carbon Monoxide) detector, not CO2 (Carbon Dioxide). Carbon Monoxide is almost neutral density but not quite. Because CO is produced by combustion such as the furnace or stove the flow of the warm air is upward. Having the CO detector at or near the ceiling is a good location.
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Bob and Joyce
2013 CC Silverback 29RL
2010 Ford F250 XL Crew Cab 6.4 liter diesel
ATU Local 788