Is a ridge vent better than a roof fan over the life of a roof?
Short answer. For most Georgia homes, yes: over a roof's 20 plus year life a ridge vent has no motor to fail, no electricity to pay for, and one continuous, low profile opening instead of a large dome, while a fan's motor and controls may need replacing along the way. A fan only wins where the roof cannot fit enough passive exhaust and the attic has generous intake.
Year one
Both can ventilate an attic that has open soffit intake. A fan moves more air on a hot afternoon. A ridge vent moves air whenever there is wind or heat, without a switch.
Years five to fifteen
- Fan: motor bearings wear, thermostats stick, solar panels lose output, and plastic domes grow brittle. Hail can crack the dome, turning it into a leak.
- Ridge vent: sits under cap shingles with no moving parts. Its main risks are short nails and missing end plugs, both installation issues.
Energy and comfort
- A hardwired fan uses electricity every summer afternoon.
- Without enough intake, a fan pulls conditioned air out of the house, and it can backdraft gas appliances.
- A ridge vent's suction is gentle enough that it rarely depressurizes the house.
At the next roof replacement
A fan's flashing is replaced with the roof, and many homeowners choose to remove the fan, deck over the opening and switch to a ridge vent. A ridge vent simply gets new vent and caps.
Never both
A fan running alongside a ridge vent pulls air in through the ridge instead of the soffits, so the two cancel each other out. If you have both, one should go.