People often talk about air sealing and insulation when it comes to attic energy efficiency, but ventilation is equally as important.
This is because attic ventilation helps push hot or unwanted air out of your attic and keeps the internal temperature consistent by bringing outside air in.
In this article, we’ll be discussing why you need attic ventilation as well as its most common types to help you find the right one for your home.
Types of Attic Ventilation
Before we get into the most common types, it’s important to understand the two different categories of attic ventilation.
Attic ventilation can be split into either active or passive categories.
Active ventilation is a system that provides indoor air circulation through mechanical fans. These types of ventilation are key for areas that are prone to moisture buildup or spaces that collect excess heat like attics and garages.
It also keeps your home free of gases and other harmful contaminants in areas where chemicals, equipment, or cars are stored.
Active ventilation provides more consistent air circulation since it doesn’t rely on natural winds to operate. Solar-powered ventilation systems are particularly useful since it runs on the sun’s energy instead of electricity.
Passive or natural ventilation is a system that uses natural methods like thermal buoyancy and air currents to provide air circulation. They typically use air vents to control the intake of air.
Passive ventilation helps regulate air temperature while bringing in fresh air and pushing out the old air. They’re cheaper than other types of ventilation and require far less upkeep.
It’s particularly useful in homes where there’s a big difference between indoor and outdoor temperatures since hot air rises and will be circulated out by the passive system.
Why You Need Proper Ventilation
But why do you need proper ventilation in the first place?
For starters, ventilation protects your roof from things like ice dams.
Ventilation reduces moisture in places like your attic. If there’s too much moisture in your attic, it can cause ice to melt then refreeze on your roofs in the winter. This causes permanent damage to your roof and compromises your overall building envelope.
Improper ventilation causes poor indoor air quality from dead air, leading to stuffier attics. It also forces your HVAC systems to work harder since hot air isn’t properly moving out of your home.
Generally speaking, if you want a more comfortable home, attic ventilation is crucial. Keeping hot or contaminated air requires proper passive or active ventilation.
Let’s now take a look at the most common types of ventilation across both categories.
Types of Passive Attic Ventilation
Ridge vents are one of the most common types of passive attic ventilation. They’re typically installed across the peak of the roof.
They usually run across the entire length of the roof. Because they’re installed on the highest point or the peak, they’re in the best position for letting hot air escape. Their length also allows them to expel large amounts of air.
Most, if not all contractors are familiar with ridge vents because of how common they are in American homes. It’s one of the most effective passive attic ventilation since it leverages the natural flow of hot and cold air inside a home.
Metal off-ridge vents are installed on roofs with three-tab asphalt shingles. They share a similar name with ridge vents mostly because they’re placed near the crest of the roof.
If anything, off-ridge vents are more akin to box vents than ridge vents. They’re not as big and can’t cover as wide of a range as ridge vents, but might work better on smaller homes or ones that are trying to increase the amount of ventilation they already have.
They’re typically about 4 feet long and involve cutting a hole the size of the vent about a foot below the vent line. Off-ridge vents are perfect for homes with lots of peaks, valleys, and dormers.
Box vents are another popular form of passive ventilation similar to off-ridge vents. Box vents also require you to cut holes in your roof. Homeowners typically install two or three box vents on their roofs for maximum ventilation.
Their small size allows homeowners to install box vents to specific areas on their rooftops, unlike ridge or off-ridge vents. This means you can be more strategic about where you place your box roofs depending on which areas need ventilation.
If you have a hipped roof or some other complicated roof design, box vents are a perfect choice.
Soffit vents are installed directly under the eaves of your roof, located underneath your roofline also known as the overhang. Almost all soffit vents have small holes that allow cool air to circulate into your attic while pushing hot air out.
There are continuous soffit vents, which cover a longer area, and individual soffit vents, which are placed in six feet intervals. Soffit vents are excellent additions to your ridge or box vents in that they provide additional vertical ventilation to your attic.
Gable vents are usually installed on the exterior wall of your attic in order to create proper air circulation during extreme climate conditions. They come in various different shapes and sizes depending on the builder and the design of your home.
Often, they are made out of wood and have screen wire for the backing. The sole function of a gable vent is to all how air to escape the attic. This prevents moisture build-up in the winter and some cooling relief in the summer.
Types of Active Attic Ventilation
Powered Attic Vents
Powered attic vents – also known as attic power vents or powered attic ventilators, are electric-propelled fans that help pull stale air out of the attic. They work similarly to a box fan on a hot summer day by pulling hot air out of your attic.
In terms of how powered attic vents fit into your overall ventilation strategy, it helps keep your attic at a constant temperature relative to the rest of your home. You want to avoid extreme temperature fluctuations up there, which powered attic vents are particularly good at.
Some detractors claim powered attic vents use up too much electricity. This concern has led to more adoption and implementation of solar-powered attic ventilation systems to provide the same cooling benefit without electrical dependence.
Solar-Powered Attic Fans
Solar-powered attic fans do away with the previously mentioned energy concerns that come with an electric-powered attic fan. They work in the same fashion as a powered attic vent, except they have built-in solar panels to harness energy to power the fan. This provides cooling benefits without the added power costs. They also qualify for federal tax credits and many other rebates.
There are a wide variety of solar-powered attic fans on the market. Pricing ultimately depends on installation costs, size, airflow, manufacturer, warranty period, and other variables. If you are interested in adding a solar-powered attic fan, we recommend scheduling an attic inspection first. An attic expert will be able to assess how many fans you need and where the fan should be installed. They will also be able to make other recommendations to ensure that your solar fan provides the most benefit.
Roof turbines, or whirlybird turbines, use aluminum blades inside of a “cowl” to rotate and ultimately pull hot air out of your attic and out into the air. There are active roof turbines that can jumpstart the blades to start spinning.
Turbine blades need to spin at about 5 to 6 miles per hour to be effective, and most homes will need multiple roof turbines to really have a noticeable effect. However, roof turbines are great at harnessing wind energy from both electricity and the outside air since the blades can be naturally propelled using wind.
Leverage Attic Ventilation Today
Installing attic ventilation isn’t just about keeping your attic cool – it can have positive effects on your roof’s lifespan as well as improving your overall home energy efficiency. Use this article to find the right type of attic ventilation and take advantage of their benefits today.