Common Types of Roof Vents for Attic Ventilation

Whether you are noticing signs of poor attic ventilation like moisture in your attic and icicles on your eaves, or you are a proactive homeowner wanting to prevent these issues, a proper roof ventilation system is a must. With the right number of intake and exhaust vents, your roof will last longer and your home will be cozier. Here is what to know about various types of roof vents, including whether your house needs more of them. 

What Is a Roof Vent?

A roof vent is an opening that allows air in or out of your attic. Roof vents are a part of your ventilation system and help with airflow, temperature control, and humidity. Every roof needs a combination of intake and exhaust vents.

One of the myths about roof vents is that they let critters and bugs into your attic. The good news is, it’s highly unlikely this will happen because the vent openings are too small.

Why You Need Roof Vents

You need roof vents to ensure your roof and attic do not get too hot or cold and to keep moisture out. There are several benefits of roof vents, including the following:

• They prolong your roof’s life.

• They reduce humidity in your attic and home.

• They improve your home's air quality.

• They keep your home at a comfortable temperature.

• They lower your energy bills.

• They prevent leaking and water damage in and around your roof.

• They reduce ice dams and icicles on your eaves.

• They maintain your roof warranties (poor ventilation may void them).

How Roof Vent Systems Work

All roof vents fall into categories: active or passive, and vertical or horizontal. Not all systems are the same and homes differ, so your local roof repair and reroofing contractor should help you determine which is best for your home, based on your home’s unique construction and size, your location, and the size and shape of your roof. They should also take into account your HVAC system, home construction materials, and other factors that determine how much venting your roof needs and how best to move air in your specific home.

Intake vs. Exhaust

There are two main types of roof vents: intake and exhaust vents. As each one serves a unique purpose, you need both for the best possible ventilation.

Intake vents allow cooler air into your attic, pushing out the accumulated hot air. Since cool air sinks below hot air, attic air intake vents should be installed lower on the roofline than exhaust vents.

Exhaust vents let hot air and moisture out of your attic—reducing the buildup of mildew, mold, and rot. Since hot air rises, exhaust vents are most effective when placed at the top of the roof, including along the ridge line. 

Active vs. Passive Roof Vents

Active systems use electricity, fans, wind-powered turbines, and other active means to draw in fresh outside air and push out warm, moist, stale air. Passive systems can be as simple as an opening or vent; they have no mechanical components, and instead rely on wind and pressure to replace old air with fresh air. Both can be effective if installed correctly and if the ventilation system includes both air intake and exhaust components. 

Vertical vs. Horizontal Air Flow

Venting systems are further classified as vertical or horizontal. Systems like soffit vents and ridge vents are considered vertical because they draw in air from below and push it out above in a vertical air movement pattern. On the other hand, gable vents and box vents that bring in air and release it in a cross-ventilation pattern are part of horizontal ventilation systems.

You cannot install both vertical and horizontal vents in your home, as the airflow patterns will cross over each other and prevent both from working correctly.

Types of Intake Vents for Roofs

Intake vents bring in cool fresh air from outside that moves through your attic and pushes hot moist air out the exhaust vents. In fact, in order for exhaust vents to work, you need ample intake vents. Otherwise, hot air can build up and cause problems in your attic space that can compromise your home’s air quality and structural integrity.

Soffit Vents

Your home’s soffit is the underside of the eaves—the part that is parallel to the ground and visible when you stand under it and look up. When you do, if your home has soffit vents, you will see thousands of tiny holes or covered round or square vents on the underside of your home’s eaves. Soffit vents are a vertical intake type and the most popular type of air intake venting systems for attics. Most are paired with ridge vents for optimal air movement. They are ubiquitous, mostly because they are highly effective, affordable, easy to install, easy to maintain, and easy to pair with any type of attic exhaust system.

Best for: Homes with soffits

Gable Vents

Gable vents are a traditional type of vent intake that may also serve as an exhaust vent.

Part of horizontal ventilation systems, which are now considered to be inferior to vertical systems, gable vents use cross ventilation to allow air in one side of the attic space and out the other.

Best for: Older style homes or in areas with a lot of wind

Over-Fascia Vents

Over-fascia vents, sometimes simply referred to as fascia vents, are one of the newest types of roof intake vents. They are best used on roofs that do not have large enough eaves to allow for traditional soffit vents. Instead, a contractor will fit over-fascia vents at the top of the gutter and fascia board, then place a shingle over top to allow air in but keep water out. These vents use the power of wind flow to bring in air, rather than rely on rising air for ventilation.

Best for: Roofs with small eaves in windy areas

Drip Edge Vents

Drip edge vents fit under or onto the drip edge, which is a roofing component that fits below the first line of shingles and helps direct water from the roof and into the gutters. Like over-fascia vents, drip edge vents are long and thin, and they rely on wind to push cool air into the intake vent where it can then move up and out exhaust vents in the attic.

Best for: Homes with small eaves or soffits

Types of Exhaust Vents for Roofs

Exhaust vents allow hot air to escape from your attic, taking with it moisture that can damage your attic, insulation, and roof. The air from intake vents will enter your home, moving through the attic and causing hot air to rise naturally. When exhaust vents are properly placed, hotter air and moisture can leave, refreshing your attic with clean air from outside.

Roof Ridge Vents

Roof ridge vents are the most common type of exhaust vent. What is a ridge vent? It is a type of attic vent that sits at the peak of the roof and covers the length of the roofline. This placement gives it two distinct advantages—it has a lot of surface area, and it is in the best position to allow hot moist air to leave the attic space quickly and efficiently. 

When comparing ridge vents vs. turbines or other smaller vents, it is important to factor in home square footage, roof ridge length, attic size, and whether active or passive venting is better for your home and situation.

Ridge vent costs vary depending on roof size, vent size, material, and roof material. Installation costs can also vary greatly, with installation as part of a new roof system being much more affordable compared to installing a roof ridge vent on an existing roof.

Best for: New homes in moderate climate areas that also have intake vents

Off Ridge Vents

Off ridge vents are vents installed close to but not on top of the roof ridge. They can vary in size, with most being around four feet long and made of galvanized steel.  While they are not as popular or effective as ridge vents or other types of attic venting, they can be a good fit for smaller roofs, roofs without a continuous ridge line (including complicated rooflines), and homes with many dormers and peaks. 

Best for: Smaller homes or homes with complicated roof lines

Box Roof Vents

Box roof vents, also called louver vents or turtle vents, are small, square-capped roof vents that are usually installed across the length of the roof. Most box vents are 18 inches square, and they are visible from the ground. Because of the number of box vents required for most homes and their proclivity to leak if not installed correctly, you will need to hire an attic fan installer near you or a professional roofer who knows how to install roof vents—box vents, in particular—in the right way.

Best for: Smaller homes with complicated roofs

Turbine or Roof Fans

Turbine vents, sometimes whimsically called whirlybird ventilation systems, have been around for more than a century, and their effectiveness and air of fun are reasons why. They are most often made with aluminum wind blades inside an aluminum shell. As the wind blows, the blades turn and pull air from inside the attic up and out.

Best for: Homes in areas with a decent amount of wind

Solar or Electric Fans 

Powered fans, whether electric or solar, use an energy source to power an attic fan that actively pulls or pushes air in or out of the attic space. Powered attic vents can be very effective with the right ventilation strategy, installation, and other venting, but the wrong system or lack of a strategy can actually make them less effective than passive methods.

Best for: Homes that require active venting

Cupola Vents

Cupolas can be a lovely addition to homes, adding style and visual appeal. Not all cupolas act as vents, but cupolas originated as dual intake-exhaust barn vents to help move air and to dry stored crops. Modern cupola vents are available in a variety of styles, including with louvered openings or open sides that allow in light, as well as designs that add to home architectural styles.

Best for: Traditional-style homes

Signs Your Roof Ventilation Isn’t Working

Your roof or attic may need more ventilation if you notice any of the following: 

• Interior leaking or moisture in your attic

• A sagging roof, loose shingles, or visible flashing

• Mildew, wood rot, frost, or water damage in your attic

• Ice dams or icicles on your eaves

• Unusually high energy bills

• Air conditioner working overtime

• Different temperatures in different rooms of your home 

• Your ceiling is hot to the touch in the summer

If you are experiencing any of the above signs, it would be smart to contact a roofing company to discuss your options. Even if you do not need a new roof, there are many types of vents that qualified contractors can install on existing roofs. You may be surprised at how affordable some vent systems are to install, and adding vents can help your roof last longer and make your home more comfortable, saving you money in roof replacement costs and home energy bills. 

How to Choose the Right Ventilation System for Your Home 

Every home is different, and you will need to take your home’s unique construction style and the climate you live in into consideration when choosing the right roof ventilation system. 

For example, a hip roof often requires a vertical airflow system, while gable-style roofs benefit from horizontal airflow. If you live in an area without dramatic seasonal changes in weather, a passive ventilation system may be sufficient. 

To get the right system, talk with a roofing contractor and ask them the following questions and any others that will give you clarification about the roof vents they are proposing for your home:

• How much ventilation does my attic need? 

• What types of roof vents are usually best for homes like mine in this climate?

• Will I need more than one type of vent for intake or exhaust?

• Where will you install the vents?

• Will the vents require any maintenance?

• How much will installation cost?

• Will the vents require electricity?

Lauren Bongard contributed to this piece.