Insufficient clearance need metal door or fireproof door to reduce clearance requirements.
Gas furnace louvered door.
Single panel full louvered doors.
Insufficient combustion air need outside air or a full louvered door or a standard door with high and low vents.
If you don t want to or can t use a louvered door here are your other options.
This is where ventilation become important not the ventilation of the furnace itself but the ventilation of the closet space.
Sometimes the door is sealed but a pipe comes into the closet to supply combustion air and that s ok.
Do not install your furnace in a storage closet.
A louvered door has horizontal slats for venting if the door is fully louvered over its entire surface then this will work as long as the combined input rating of the gas appliances is less than 175 000 btu hr.
Door furnace 22 x 78 5 finished opening size 22 5 x 80 5 free air space.
Combustion air can be drawn from adjoining spaces.
The heat that the furnace radiates may lead to a fire hazard.
You can connect the furnace room to the rest of.
For a 100 000 btu furnace gas fired or oil fired than a 50 square inch fresh air vent is required.
Therefore the above would reqiure 100 sq inches.
Electric furnace no combustion.
Some furnaces allowed off sleeping areas with outside air and solid sealed fireproof door.
Sometimes there is a small grill in the floor that some goof covered up with a piece of carpet that was not ok.
Fresh air is required.
For a gas or oil furnace a louvered door or a pipe to supply combustion air is required.
White finish is electrostatically applied baked on enamel.
Note if a louver is used than this will decrease the size of the opening.