Attic Ventilation: Venting Hot Air

Attic Ventilation is essential for exhausting hot air, to ease the load on the air conditioner, and to lower utility bills. This can be done with roof vents and fans.

There are two air flow components that work in tandem to vent hot air from inside the roof to the atmosphere: the air inflow component and the air exhaust component. If these are balanced, two things will happen.

The first thing is that heat will be reduced, resulting in lowered energy consumption because of fewer air conditioning cycles. The second thing is that the circulating air minimizes the possibility of humidity and moisture build-up. The chance of mildew and toxic mold are thus reduced.

Air Inflow Components: Soffit Vents

Soffit vents are the most common method of providing an entry point for exterior (cooler) air into the roof space. These are rectangular rigid-louver vents with a screen, usually fiberglass, to keep bugs out.

They are attached to the horizontal surface of the home's soffit between rafters. Ideally, they should be evenly spaced between every other rafter for best air flow. They're easy to install. Mark the spot with a template, cut it out with a jigsaw, and attach it to the soffit with coarse-thread drywall screws.

It's important to ensure that the opening isn't blocked by attic insulation.

Air Exhaust Components

Turbine vents - Traditionally, the most common device used to draw hot air from the attic, it's also called a whirlybird fan. It operates in a simple manner; the top part is a metal globe with fins. The fins are angled to catch the wind and spin the globe on its base.

The spinning action draws the air from the soffit, through the attic, and exhausts it to the atmosphere.

Ridge vents – Ridge vents are commonly used nowadays to vent the attic space in both new construction and on re-roof jobs. They're mounted along the home's roof ridge and blend in nicely since they're covered with matching shingles.

They're equipped with a baffle to keep external weather such as rain from entering the attic. The baffle also creates low pressure, which helps draw the hotter air out.

Power roof vent – The power roof vent draws the air out in a similar spinning fashion to the turbine vent, but doesn't depend on the fickle wind to power it. This vent is triggered on and off by a thermostat mounted inside the attic and is powered by the home's electrical circuitry.

Solar powered roof-mount attic vent – These units are similar to their utility-provider powered model except that they depend on a solar panel. This puts them in the green-building practices arena since they use a renewable power source.

Gable-mounted power attic vent – Like the power roof vents just covered, there are two types of gable-mounted units, one wired to the home's circuits and the other solar powered. The difference is that they are mounted vertically on the gable, the triangular wall area between the two sides of sloping roof line. The better models include a humidistat in addition to a thermostat.

Ridge Vents

Print Article

Email Article

View All Articles

How to subscribe to feeds