Take a Breath Already: The Three Golden Rules of Attic Ventilation

The Top Attic Ventilation Tips

Your roof is quite a bit more complex than it may appear at first glance. Not only must it keep water out, it must also allow air to flow through. In fact, the main goal of attic ventilation is to create enough air flow that the temperature in the attic is as close to the outside temperature as possible.

When functioning properly, a well vented attic will keep your home cool in the summer, and mitigate ice damming in the winter. It will also help maximize the service life of your shingles. Alternatively, a poorly vented attic can turn your house into a sauna, bake your shingles to a crisp, and promote ice damming and condensation issues. Luckily, adding vents to your roof is a breeze (no pun intended). Just follow these simple three steps!

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The 3 Golden Rules of Attic Ventilation

1) Balanced is Best.

A properly vented attic has a 50/50 split between intake and exhaust. So, if your soffit has 1000 square inches of intake vents, then your roof should have 1000 square inches of exhaust. Many people make the mistake of cutting in extra exhaust vents in an effort to increase air flow, but ignore their intake vents. Unfortunately, extra exhaust vents aren’t very effective if you don’t have enough intake to match it.

The rule of thumb when sizing up your roof for ventilation is 1:300—that is, 1 square foot of free air space (ventilation) for every 300 square feet of attic floor space. And, that 1 square foot should be divided equally between exhaust and intake. Make sure you consider both sides of the equation before you start making changes to your ventilation system!

2) Don’t Mix It Up.

Roof vents don’t play well with others. In fact, they flat out discriminate. Alright, maybe I’m being a little dramatic, but it’s important that you don’t mix different types of vents on the same roof. Why? Well, it all goes back to that balanced system we’re trying to achieve.

Using the same exhaust vent across the entire roof will contribute to a balanced, evenly vented attic. Mixing vents becomes especially problematic when you combine static vents—like turtle vents—with dynamic vents, such as turbines. You want the turbine to pull fresh air from the soffit vents at the base of the roof. However, if a turtle vent is closer to the turbine than the soffit, guess where it’s going to pull from? That’s right, the turtle vent.

Air will always take the shortest, easiest route. Make sure your exhaust vents are all working equally as hard so that they don’t turn into unintentional intakes.

3) Stay on the Same Level.

Always install all exhaust vents at the same height on the roof. Once again, it’s all about that balanced system thing. This goes right back to the idea we touched on previously, about inadvertently turning exhaust vents into intake vents. If exhaust vents are installed at multiple heights, then the vents in the middle will tend to become intake vents for the vents at the top. Once again, your system will be out of whack, and you’re left with a poorly vented attic space.

This is where different vent types start to come in. If you have a small hip roof with limited space at the ridge, you may need to select an exhaust vent that moves a higher volume of air—a turbine, for example. If you have a long gable roof with miles of ridge, then a higher quantity of static turtle vents will be just fine. Each roof is unique and comes with its own challenges.

Perfect Your Attic, Perfect Your Home

A poorly vented attic can have some fairly negative consequences and severely impact the comfort of your home. Fortunately, those issues are easy to avoid! Doing it right is as simple as 1 – 2 – 3.

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