DefinitionFurnaces, water heaters, wood stoves, and other devices that employ combustion-burning fuel are vented to the outside in a manner that meets manufacturer specifications to prevent back-drafting. Natural and/or mechanical ventilation delivers fresh air to every habitable room and bathroom to remove moisture laden air and other contaminants generated during cooking and bathing/showering. The air exhausted from a bathroom, toilet room, or kitchen does not vent into habitable space or an attic.
Terms and DefinitionsGenerated May 4, 2026