If the furnace and/or hot water heater is located in a small closet type room, it must have adequate air supplied through vent pipes from the attic, louvered doors to the room, or a large air vent in the wall.
Combustion Air Requirement
- Unconfined space – minimum 50 cubic feet of space per 1000 btu per hour.
- Confined space – two openings 100 square inches each, freely communicating with unconfined space.
The total BTU’s from both units must be calculated.
NOTE: If combustion air is brought in using pipes they must be installed as follows. Vent or breather pipes to the attic must extend above the insulation. One pipe should terminate 12 inches below the ceiling, and the second pipe 12 inches from the floor.