Recently moved into home in Eastern MA(Zone 5?) and have a 2 story 3K sqft home. There are 3 gas furnaces and AC units. One of the furnaces is in the attic. The roof is a "T" shaped Gable roof. The roof at "top" of the T has soffit vents and a ridge vent. The "stem" of the T has soffit vents and *no* vent at top. The furnace is located in the stem. That roof has a flat roof top. The furnace itself has a vent stack penetrating through the flat roof; label reads "American Standard Freedom 80 Single Stage". I don't see an intake pipe so I'm assuming it's not a sealed burner. What's concerning is that there is no venting of the attic area where the furnace is. Roofer suggested installing a powered gable vent. Will this be an appropriate way to vent this area? Will there be conflicts with the ridge vent in the other roof system? Will there be issues with the furnace or pull air from the living space?
Top Attic measurements: 30' x 25'
Stem Attic measurements: 24' x 34'