I have just finished my basement and my furnace is now in a room about 20 x 20. I had installed double doors (solid not vented) to enter the room which is also being used for storage.

My question is do I need to add some kind of makeup air for combustion by installing a grill in the wall? How do I know how large I need? Is there a way to calculate this? The heater is a 125,000 BTU york furnace about 2 years old.

Thanks for any help.