Broan vents are exhaust fans used for bathroom and kitchen ventilation — not attic ventilation. They’re a different category entirely, but they penetrate your roof and they matter to both your roofing system and your indoor air quality.
In a bathroom, a Broan vent exhausts humid air — steam from showers, moisture from daily use — out through the roof. In a kitchen, it exhausts cooking fumes and heat through a roof or wall penetration. Both use a flapper mechanism that opens when the fan runs and closes when it’s off, preventing outside air from coming back in.
Why your bathroom might seem like it’s leaking in winter:
This is one of the most common calls we get in cold months. Homeowners notice water staining around their bathroom vent or moisture on the ceiling and assume the roof is leaking. Often it’s not — it’s condensation.
Here’s what happens: warm, moist bathroom air is pushed through the exhaust duct toward the roof. In winter, that duct passes through a cold attic space. If the duct isn’t properly insulated, the moisture in the air condenses inside the duct before it ever reaches the outside — and that condensation drips back down into the bathroom or attic. It looks exactly like a roof leak. It’s not.
The fix is usually insulating the exhaust duct through the attic, making sure the vent terminates properly through the roof rather than into the attic space, and ensuring the flapper is functioning correctly. During a re-roof, we inspect every penetration including bathroom and kitchen exhaust vents — and when we find issues, we address them. A re-roof is the right time to correct these details, not after the new roof is already down.