Furnace Venting Into Attic

In this video my hvac contractor gilbert rosipal from airrite shows us the inner workings of a 95 efficient gas furnace.
Furnace venting into attic. Cut 1 inch deep slots a few inches apart along the top side. If you re preparing to upgrade an old furnace it might be time to consider moving it back down to the ground level. Now cut 2 inch deep slots. However the furnace is in an attic space which has no venting for warm humid air from house from soffits from hot roof etc to escape.
You ll see the concentric pipe used. Insulation is only so effective in preventing the heat in the house from going up into the attic. Bend these newly cut tabs in. You ll start to save money on your heating costs too and your furnace will perform closer to its indicated seer.
That is because with an attic installation vents must go down into the thermal envelope to deliver warm air. The furnace has a stack which penetrates the flat roof and is about 3 4 above the roof plane. Fresh combustion air for the furnace is coming from the soffit vents from both roofs. Yes in fact this is the most efficient manner of providing air to your furnace.
Unwrap the flashing from the vent pipe so you can work with it. Cut enough aluminum flashing from the roll to wrap around the vent pipe with an extra 6 inches to spare.