When we think of a roof, we tend to think of covering and protection. But just as important are the roof’s openings that allow for air flow—also known as ventilation.
If you’re considering updating or replacing your roof vents—or you’re installing a new roof altogether—there are a number of factors to consider before making your selection. Here we’ll give you some of those specifics as well as our top 10 recommendations.
What is a roof vent, anyway?
A roof vent is a system built into your roof that allows for air movement in and out of your roof. Its primary purposes are to keep the interior of your roof dry and its temperature regulated.
A roof vent system has two parts: the exhaust (through which warm air exits your attic) and the intake (through which fresh air enters your attic). Both are critical for a healthy and long-lasting roof.
What can happen if I have poor roof ventilation?
If your roof doesn’t have proper ventilation, hot, humid air will get trapped in your attic. Hot air contains moisture which in time will cause mildew (which smells bad) and then mold buildup (which causes wood damage).
In cold weather, ice dams can also form along the edge of your roof as the hot air causes precipitation on the roof to melt, then re-freeze as it reaches the edge of the roof. Ice dams can loosen your shingles, weigh down your gutters, and even cause water damage to your roof.
Other effects can include poor air quality in your house and an overworked HVAC system.
What factors should I consider when choosing a roof ventilation system?
Which type of roof vent you choose depends on a variety of factors, most prominent of which is the roof design you have. Certain systems work with shingles but not with tiles. Others apply better if your roof has certain features like gable or soffits.
Another factor worth considering is the appearance you want your roof to have. Some air vents are more conspicuous than others, which you may like or not like.
Also take your climate into account. High winds can damage your turbine. Rain can be blown into soffit vents and gable vents, threatening water damage. So consider a system that can withstand the elements it will be subjected to.
When it comes to how much ventilation your roof should get, remember what’s called the “1/300 rule”—1 square foot of attic ventilation for every square foot of attic space.
What are the different types of roof vents?
Intake vents
Intake vents do just that—take air in. The incoming cool air pushes the hot air up (which it is inclined to do anyway) and out of the exhaust vents. This is why intake vents are placed lower on the roof and exhaust vents near the top.
Soffit vents
Soffit vents are the most common type of intake vent, because they tend to be the most effective and efficient. Soffits are vents that are installed directly on the roof’s eaves (or overhangs) and typically take the form of holes drilled into vinyl.
Continuous soffits in particular wrap around the entire eaves of a house and allow for lots of air flow into the attic.
Drip edge vents
A drip edge vent gets installed directly under the first row of shingles along the roof line with the intention of helping water drain into the gutters. It’s typically used when the roof’s eaves are not large enough for a soffit vent.
The benefits of a drip edge vent are primarily that it takes in air as it hits the roof head on, rather than require it to move in an upward trajectory like a soffit vent. However, drip edge vents are also typically significantly smaller than a soffit vent, so it may take in less air.
Over fascia vents
An over fascia vent is very similar to a drip edge vent in that it’s a smaller strip designed to take in air head-on. So the benefits and drawbacks are identical.
The only difference is over fascia vents are installed directly above the gutter.
Gable vents
Gable vents are utilized on gable roofs (not surprisingly) because they can be placed on both sides of the roof.
They come in handy for gable roofs but don’t work well in tandem with other attic vent systems, primarily because the cross-breeze created by the two gable vents can actually prevent hot air from escaping up through a vent on the top of the roof.
Exhaust vents
Ridge vents
A ridge vent is the most common type of exhaust vent. A gap is sawn into the ridge of the roof to allow hot air to escape. It utilizes the natural flow of hot air (i.e. upwards) and provides an easy way for it to exit the attic.
Wind turbine vents (aka “Whirlybirds”)
Wind turbine vents—also known as “whirlybirds”—are aluminum contraptions situated atop the roof that utilize the wind to power a turbine that functions to pull air up and out from the attic.
Whirlybirds have the advantage of being naturally powered and relatively quiet even as the operate. But the downside is that they generally require wind speeds of at least 5 mph.
Power vents
Power vents function in a similar way to turbine vents in that they generate an upward pull of air. The major difference is that power vents are fueled by electricity or solar panels.
They have the advantage of not requiring wind power, but they can run the risk of over-drawing air out of the house and increasing your energy bill (not to mention your electric bill if it’s an electric vent).
Box vents
Box vents—also known as Louver vents—are square-shaped vents that get installed near the roof ridge. They are probably the second-most common exhaust vent behind ridge vents.
Box vents come in handy if the area in need is relatively small and/or when a ridge vent doesn’t fit well. But they are quite small and thus don’t let as much air out as quickly.
5 Roof Vents to Consider
- Lomanco 12-inch Whirlybird
- GAF Cobra Ridge Vent
- Broan-NuTone 3 in to 4 in Roof Vent Kit
- QuietCool Thermostat Controlled Gable Fan for Attic Cooling
- Ventamatic 1600 CFM Mill Electric Powered Gable Fan
Leave it to the professionals
Homeowners who don’t fancy themselves DIY super-roofers are best off calling a trusted local roofing company. If you’re in the South Sound, give us at Acme Roofing a call!