I removed an old coal furnace from my basement. The furnace did not have any duct work to speak of. There was an exhaust pipe which fed into the chimney and a duct that went into the next room, but for the most part all the heat went up through a 30" x 30" hole in the ceiling above it. The hole is covered by a floor grate without any filter or louvers.
My house is 1100 sqft and reasonably well insulated. Can I install a new gas furnace to use this same hole? Is there a particular type of furnace that would work best for this application? Do I need to worry about a cold air return? I'm assuming I would need to add some kind of filter. I would greatly appreciate any general advice on how to approach this project. Thanks in advance.
Best Answer
The question being "can you?", my answer is "yes, you can". There's no reason a gas furnace can't be run with a single air outlet. In fact, it's common for folks in my area to repurpose older furnaces as garage/workshop heaters, often with nothing but the upper plenum or perhaps a single duct run to a convenient location. Return air is simply scavenged from near the floor.