Would appreciate any information on the following:
Will be replacing a very old gas, forced hot air furnace with a new "high-efficiency" type.
Have just read in the Audel's HVAC manuals that for a "high-efficiency" type of hot air furnace, you do not vent thru the chimney (or via a metal vent pipe that goes thru roof like we now have), but rather you vent via a PVC pipe thru the side of the house. It wasn't worded such that you might think that this is an an option, but rather that this is the (only) way to do it.
Has to do with the fact that the gas is not very hot from these types of furnaces, and the condensate would flow back and ruin the furnace, etc.
Is it the "only" way ?
Is there a "mid-efficiency" forced gas hot air furnace that would enable venting in the manner we now are doing it (thru the roof) ?
Sure don't want the expense of trying to configure a new vent thru the back side of the house !
If so, how would these "mid-efficiency" furnaces be designated: by SEER Number, or... ?
Any thoughts on this would be most appreciated.