Exhaust Vents | |
Exhaust vents are designed to permit an efficient, unobstructed outflow of attic air. In addition, because theyre installed high in the attic where there's greater exposure to the weather, these units must be designed to prevent (or at least minimize) rain and snow infiltration. Exhaust vents must be used with intake vents to provide proper high/low balance and thus an adequate flow of air through an attic.For maximum efficiency, the net-free area of the exhaust vents must be equal to the net-free area of intake vents. As with intake vents, exhaust vents are available in different designs. The two most commonly used fixed exhaust vents are: Roof vents which are installed as close to the roof ridge as possible to allow maximum release of moisture and over-heated air. Because they're installed near the ridge, they provide a continuous air flow along most of the underside of the roof sheathing. The air flow pattern isn't uniform, however, so for maxiinum effectiveness, vents should be spaced equally along the roof. (Figure 14.) Louvers which are typically installed in gables. Two types are available: rectangular and triangular. In most installations, a unit is placed at each gable end. Source: Air Vent Inc. A Certainteed Company Reprinted with permission, HouseNet, Inc. |