What Is Power Attic Fan?
A power attic ventilator is a motorized exhaust fan, usually with a thermostat, that moves far more air than a passive vent. Roof-mounted units sit in a flashed dome; gable-mounted units sit behind a louver. Two things decide whether one helps. First, intake: a fan without enough soffit intake depressurizes the attic and pulls air from the living space through every gap in the ceiling, raising cooling bills. Second, the flashing: a roof-mounted fan is a large penetration, and the dome's flange has to be shingled in like any other roof penetration, not surface-mounted and caulked. Solar-powered units remove the wiring and the operating cost and run when the sun, and the attic heat, are highest; their airflow is lower than a wired unit. A power fan is not a substitute for a balanced ridge-and-soffit system on a new roof; it is a retrofit for attics that cannot be vented passively.
Important Distinction
Note: This describes the component in general. Which product, gauge or detail a specific roof needs is a job-by-job determination made after an inspection, and the building code and the manufacturer's installation instructions govern over any general description.
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Also Known As
These are the search terms and phrases that commonly refer to this topic, so you can find it however you describe it.
How Power Attic Fan Relates to Other Topics
A power fan without intake pulls conditioned air from the house.
A roof-mounted fan is a large penetration; surface-mounted and caulked flanges leak.
Solar units are the unwired form of the power attic fan.
Questions about Power Attic Fan?
Zilker Roofing inspects before recommending. Honest assessment, no pressure.