One carbon monoxide detector is required on each living level of the home, including “walk up attics” (those with a staircase, not pull down stairs).
The carbon monoxide detectors must be within 10 feet of a bedroom, but not located in a bedroom unless it is an additional detector. Carbon monoxide detectors are not to be placed within 10 feet of a carbon monoxide producing appliance, ( furnace, gas stove, etc.) and also is not to be placed within 10 feet of a garage, under or attached.