A properly-ventilated attic is a necessary part of keeping your home comfortable and maintenance costs under control. Proper ventilation keeps the air temperature and dew point in your attic similar to that of the outside air, helping minimize your heating and cooling costs, as well as prolonging the life of your roof and shingles. Many experts agree the best way to provide proper ventilation in your attic is through a combination of soffits all along the bottom edge of your roof and ridge vents along the top.
How Does Attic Ventilation Help My Home?
Improperly-vented attics end up with air and moisture trapped inside them. During the summer, with the sun beating down on the roof, the temperatures in your attic can get as high as 160 F, forcing your air conditioner to work extra hard while baking the underside of your roofing and shingles—shortening their lifespan.
In cold weather, warm, moist air rising from your living area is trapped in your attic and will help melt the snow on your roof on sunny days. When the outside air temperature drops, this melted snow freezes into ice and eventually could cause an ice dam that will ruin your shingles and roof sheathing.
So What's a Ridge Vent?
A ridge vent is exactly what the name implies: it's a vent or opening installed in a continuous line along the peak or ridge of your roof. Installation requires removing the top inch or so of the roof on both sides of the peak, creating a long opening to be covered by the ridge vent.
The vent has screened openings to keep leaves and animals out and is covered with small shingles (called ridge caps) that match the shingles on the rest of the roof, making the ridge vent virtually invisible from the ground.
The continuous opening provides a totally passive and maintenance-free way to allow air migration from your attic.
Why Is a Ridge Vent Better Than Other Roof Vents?
Although almost all homes have some form of attic ventilation, it is usually not enough to meet today's building standards, which call for proper attic ventilation to have a ratio of 300:1 (for every 300 square feet of floor space you should have 1 square foot of ventilation).
A ridge vent's continuous opening along the top edge of the roof allows a more-than-adequate amount of ventilation. In addition, since ridge vents don't have any moving or mechanical parts, they can't injure birds and never require periodic maintenance to stay working. Besides that, their being invisible means there are no unsightly vents sticking up from the roof.
Ridge Vents Need Air Flow to Provide Proper Attic Ventilation
A ridge vent can't work in isolation, and, for it to work properly, there needs to be a continuous flow of air from the bottom edge of the roof (in through the soffits) up to the peak of the roof. If the openings in the soffits are covered by insulation, blocking the airflow, the ridge vent can't work properly.