Georgia Roof Guide

Can an exhaust fan vent through a ridge vent?

Short answer. No. A bathroom, kitchen or dryer exhaust should never discharge into a ridge vent, soffit or attic; the International Residential Code (Section M1501.1) specifically bars it, because the moist air condenses in the attic instead of leaving. A powered attic exhaust fan also should not be added to a roof with a ridge vent, since it pulls outside air in through the ridge and short circuits it.

Bath and kitchen fans

Exhaust fans move warm, wet air. Aimed at the ridge vent from below, much of that air hits the cold deck first and condenses, especially on winter nights. The ridge vent's filter also slows the flow, so moisture lingers. The result is black staining along the ridge, rusty nails and sometimes drips onto the ceiling. The right setup is a sealed duct from the fan to its own roof cap or wall cap with a backdraft damper, with the duct insulated in the attic.

Powered attic fans with a ridge vent

A powered attic fan pulls air from the easiest source. With a ridge vent nearby, that source is the ridge itself, so outside air flows in at the top and straight back out while the lower attic stays stagnant. During storms, the fan can even pull rain in through the ridge vent. With a ridge vent and good soffit intake, most homes do not need a fan at all.

What to do if yours is wrong

Learn the bigger picture in roof ventilation basics and attic heat and shingles.

In depth

Ridge vent or box vents: which is better, and can you use both?Ridge vents vs box vents, turbines and power fans for Georgia attics: how each works, why mixing exhaust typesHow much attic ventilation does a Georgia roof need?Attic ventilation for Georgia homes: intake and exhaust balance, the IRC R806 1/150 and 1/300 rules with workeDoes a hot Georgia attic shorten the life of your shingles?How hot Georgia attics and shingles get, what research says about ventilation and shingle life, and when radia

People also ask