Originally Posted by Bowmans
Whatever you get, make sure the CO2 detector(s) are mounted low to the floor and the smoke detectors are high near/on the ceiling. We had a CO2 detector that came with ours but replaced in 2000 which was wired to the batteries in the camper and we added another 9 volt one back in the bath area. We also got 2 9 volt smoke alarms and mounted them to the center ceiling front and back.
I think she was asking about CO detectors, not CO2. Different instrument for detecting different gas.
When considering where to place a carbon monoxide (CO) detector, keep in mind that although carbon monoxide is roughly the same weight as air (carbon monoxide's specific gravity is 0.9657, as stated by the EPA; the National Resource Council lists the specific gravity of air as one), it may be contained in warm air coming from combustion appliances such as home heating equipment. If this is the case, carbon monoxide will rise with the warmer air.
Read the instructions for your detector for correct placement.