Your roofing system needs balanced attic ventilation to perform at its best.
When you’re replacing your roof, ask your contractor about ventilation options for your roof and attic. They should offer several ventilation products for you to consider, ensuring you have a balanced system of intake and exhaust vents.
Be prepared to discuss ventilation options with your contractor by understanding the different types of roof vents necessary to create a balanced attic ventilation system.
Learn more about attic ventilation and why it’s important for your roof and home.
Roofing and Attic Ventilation Products
There are several types of roof and attic ventilation products available for your home. You’ll often see them referred to as:
- Roof vents
- Attic fans
- Gable vents
Attic and roof ventilation products are categorized as either:
- Intake ventilation
- Exhaust ventilation, or
- Both intake and exhaust
Why do I need intake and exhaust vents for my attic?
Every attic ventilation system should have a combination of properly placed intake and exhaust vents.
Roof vents and attic fans work year-round to:
- Remove warm, moist air
- Reduce condensation
- Keep your attic drier
- Allow pressurized heated air to escape so it doesn’t force its way into conditioned spaces
The key to ideal ventilation is having the correct amount of both types. Having only one or an uneven amount of one type of venting can lead to pressurization problems.
Pro Tip: Use our Ventilation Calculator to help determine how much ventilation you need for your attic.
It’s just the attic, though, who cares?
Depending on the shape of your roof and architecture of your home, either a section or the entire underside of your roof deck is exposed to your attic space.
Attics may often be seen as unconditioned storage spaces. While that may be true for some homes, especially those with rafter framed attics, some “attics” are little more than gaps between the ceiling and roof deck. Big or small, these spaces need venting to manage heat and moisture inside the structure as well.
Without correctly balancing the amount of intake roof ventilation with exhaust roof ventilation, moisture can build up in your attic, leading to a potential host of problems, including:
- Damage to the structural integrity of your roof
Pro Tip: Ask your contractor how to ventilate an area above a cathedral ceiling or other small attic space.
Intake vents do just as their name suggests — they take in air from the outdoors. This fresh air goes into the attic and replaces the air that went out from the exhaust vents, helping to ensure balanced airflow.
Intake vents are typically placed under the eaves of the roof. They help the exhaust vents in the attic do their job more effectively and assist in controlling energy costs.
There are two types of intake vents: soffit vents and roof-mounted intake vents.
Soffit vents are the most common type of intake roof vents, and they’re placed underneath the roof eaves all along the length of your house or between the joists.
Pro Tip: If you have blown-in insulation, make sure it doesn’t restrict the airflow to the soffit vents.
Roof Intake Vents
If your home has no soffit or exposed rafters under the eaves, a roof mounted intake vent can be used to provide adequate air intake.
These vents have a low profile that blend into the roofline.
Exhaust vents allow air to flow out of the attic to the outdoors. Attic fans and ridge vents are two examples of exhaust vents, and these are typically placed higher on the roof, often the highest pitch where hot air tends to gather.
Ridge vents, as the name implies, run along the very top of a roof on the ridge, typically where the two sloping portions of a roof meet. They’re ideally placed to catch the wind blowing over the roof, which helps expel moisture and heated air from the attic.
Static Roof Vents or Roof Louvers
Static roof vents or roof louvers permit air to escape the attic and are placed flat on the roof and evenly distributed near the ridge.
You might find these listed under various names depending on the region in which you live, such as:
- Box vents
- Turtle vents
- Off-ridge vents
In the western U.S., they’re frequently called dormer vents.
Wind or Roof Turbines
Wind or roof turbines have blades or vanes built in. The wind turns these blades, creating a spinning vacuum that helps draw out hot, moist attic air.
Attic fans are typically located on a wall inside the attic. Their job is to pull air from the attic and vent it to the outside. Attic fans can move large amounts of hot or humid air from an attic, which can help keep your heating and cooling costs in check. Homeowners can gain more control over ventilation by turning attic fans on and off as needed.
Powered Roof Vents
Powered roof ventswork on the same principle as attic fans; however, they’re located on the roof.
Although a more expensive option, powered roof vents can be configured to run off electrical or solar power. The added mechanical force behind these roof vents can significantly increase air circulation, potentially saving you money in the long run.
Pro Tip: Powered fans pull a lot of air, so it’s critical to have adequate intake ventilation to provide enough outside air to balance airflow; otherwise, these powered vents can create a vacuum in your attic that pulls conditioned air out of your house.
A few vents, such as gable vents, serve as both intake and exhaust vents, depending on wind direction and speed.
How Balanced Attic Ventilation Works
Now that you’re familiar with the different types of intake and exhaust ventilation products for your roof and attic, let’s take a quick look at how balanced attic ventilation works.
Imagine it’s a summer day and you leave the front door of your house open so you can unload and bring in groceries from the car. Your house windows are also open, and there’s a breeze blowing outside. Suddenly, the front door slams shut, probably scaring you in the process.
Your home was drawing in air through the open front door to replace the air leaving through the open windows — it was ventilating.
This is exactly what is happening in your attic through your intake and exhaust vents. First, air is released from the attic to the outdoors through the exhaust vents, creating a vacuum. Then, fresh air from the outside rushes back in through the intake vents, filling the vacuum.
If you don’t have the right amount of intake vents or if they’re blocked, air may be pulled from your living spaces to help balance the pressure. Likewise, if you don’t have the right amount of exhaust vents, warm pressurized air from the attic can make its way into your conditioned living spaces. Both scenarios are not energy efficient and can potentially impact your home’s energy costs.
If you find yourself constantly adjusting your thermostat, then you may have a ventilation issue.
Learn more about attic ventilation in our article “Why Balanced Attic Ventilation is Important for Your Roof”.
Pro Tip: Bathroom and kitchen fans must vent outside through the walls or roof rather than into the attic. Ask your contractor to check your attic for improper venting from other parts of your home and signs of excess moisture.
Roof Vents: The Bottom Line
As you can see, the key concept in proper roof ventilation is balance. To achieve balanced airflow through your home’s attic spaces, you need the correct amount of intake and exhaust vents. Roof intake and exhaust vents work together to help remove warm, moist attic air and replace it with fresh, drier air. In the process, air pressure remains equalized.
If you notice any signs of improper ventilation in your home, talk to a roofing contractor. They can check for airflow obstructions or see if you need additional vents of one type or another. Also, make sure to discuss ventilation solutions with your roofing contractor before beginning a roof replacement.