Hot, moist air is not friendly to wood rafters, trusses and roof sheathing. Without adequate ventilation, humid attic air reduces shingle life and increases the risk of truss uplift and joist movement. Turbine vents are not new to the roof ventilation scene, and many homes built after 1950 feature turbine roof vents. As homeowners sought to increase aesthetic roof appeal, though, many bypassed turbine vents, which are more visible and less attractive than sleek, low-profile vents.
While wind turbines fall into the exhaust vent category and are effective at drawing out stale attic air, you’ll need additional vents for the turbines to operate effectively. The vent features a hollow stack rising a few inches above the shingles. At the top of the stack is a turbine that acts much like a child’s whirligig, spinning rapidly during even the slightest breeze. Some vents have a protective housing covering the turbine, while others feature small louvers that open only when the wind blows and close when the turbine is at rest.
Turbine vents are highly effective when combined with low wall or soffit vents. When the wind isn’t blowing, hot air can still rise and escape slowly through the vent. With a breeze, the sucking motion created by the spinning turbine can quickly remove moist stagnant air, drawing in new fresh air from the lower vents.
A turbine vent sits high on the roof, close to the ridge, and the turbine stack may rise above the ridge line. Taller stacks create a stronger draw but need additional roof support to withstand the force of high winds. The installer cuts a hole in the roof and inserts the vent stack, securing it to the roof sheathing. The vent features a base flange that tucks beneath the upper shingles and rests on top of the lower shingles to encourage rain to run down the roof and not into the vent opening.
Pros and Cons
Turbine vents are more effective than other types of roof vents, but they can be noisy because they have spinning parts. While the turbines are popular in commercial settings, some homeowners prefer low-profile roof vents installed on the backside of the roof where they won’t be seen from the street. Turbine vents usually shed water, even in driving rain, because the force generated by the spinning turbine keeps rain out of the vent stack. Old turbines can stick or rust, which can lead to leaks.