Materials & Shingles · FAQ

Ridge vent or solar attic fan: which works better in Illinois?

Ridge vent, almost always. A continuous ridge vent moves 700 to 1,000 cubic feet of air per minute across a typical Madison County roof on a normal summer day, driven by natural convection. A solar attic fan moves 800 to 1,500 CFM on a sunny day and zero on a cloudy one. The math favors the ridge vent on cumulative airflow, and ridge vent has no failure modes.

Trill’s metrics on installed homes: ridge vent drops peak attic temperature 25 to 30 degrees versus pre-install. A solar fan added to a poorly vented attic (no soffit intake) drops temperature 10 to 15 degrees. A solar fan added to a properly vented attic adds nothing measurable because the ridge vent is already moving the air. Save the $400 to $700 the fan costs and put it toward more soffit intake instead.