Combustion Air

srecord1

I am finishing my basment the furnace and water heater is in is 18x12 room by them selfs and planing to close off that room with a door. the furnace is a high-efficiency furnace 92 %. instead of using the port on the furnace for combustion air they installed a duct to the furnace room that is 10x10 round. my question is...... is that enough air for the 120000 btu furnace and the 40000 btu water heater that are in that room? that duct is about 19 feet long with a metal grill to the outdoors or should I go threw the trouble of installing the PVC combustion air line? also the duct is about 12" from the ceiling of room and has one elbow that points down to the floor ceilings are 8ft high

beenthere

Its too small.

Affordable7

I would install the combustion pvc line to the furnace to the exterior of the building...and extend the 10" pipe from the ceiling down to right inside the top lip of a 5 gallon bucket (this will trap the cold air until it is needed...instead of continuous flowing making that room very cold).