What Is Attic Ventilation?
Photo credit: National Contractors

There are two sides to every story, but what homeowners may not realize is that there are also two sides to most roofs, too. Beyond the professionally installed roofing system that protects your house from water on the outside, an attic ventilation system works from the inside to protect your home from heat and moisture. 

What Is Attic Ventilation? 

Through a balanced system of intake and exhaust vents, proper ventilation lets your attic, and your entire home, breathe. The word "ventilate" originates from the Latin word meaning "to fan." Ventilation moves hot air out and cool air in, replacing stale, overheated air with fresh air from outside. 

How Does an Attic Ventilation System Work? 

Hot air rises naturally, so intake vents located at the bottom of your roof under the soffits allow cool air from outside to enter the attic. This fresh air keeps flowing through the attic before escaping back outside through the hot air exhaust vents, which are located on the top of the roof. 

Photo Credit: GAF

This is a natural process called passive ventilation, one of the most common and effective ways to achieve a balanced attic ventilation system. The amount of exhaust ventilation at or near the roof ridge should never exceed the amount of intake ventilation at or near the roof's soffit. 

Why Is Attic Ventilation Important? 

If your attic is not properly ventilated, the space can reach more than 160 degrees Fahrenheit, particularly in the summer heat. Without adequate ventilation, a buildup of heat and moisture in the attic can cause stress to the shingles, your roof system components, and structural supports, potentially causing premature deterioration and reducing their service life. A balanced and effective attic ventilation system allows cooler, fresh air to enter the attic, forcing out superheated air, which helps protect your roofing system. 

During the winter months, the hot, moist air in your attic along with the sun, can heat up your roof and melt the snow that accumulates on it. When that running water then refreezes as temperatures dip, ice dams can form on the colder roof edges under the eaves. These ice dams can also cause water to work its way back up under your shingles, damaging the roof and potentially leading to leaks inside your house. Allowing frigid winter air to pass through the attic keeps your roof's temperature cooler and helps prevent the cycle of snow melting and refreezing that can cause damaging ice dams. 

Here are a couple of more reasons why ventilation is so important. 

It Reduces Excess Moisture

As we go about our daily activities, such as cooking, showering, and even breathing, we emit gallons of water into the air. That moisture can make its way up into your attic. 

Once that moist air hits a cooler surface, such as the underside of your roof deck, condensation forms. As this condensation accumulates, it can cause nails, flashing, and duct straps to rust, resulting in damaging leaks. Excessive moisture will promote mold, mildew, and even wood rot under your shingles. Your roof's insulation can also absorb humidity, reducing its effectiveness. 

Proper ventilation for your attic helps remove this water vapor from your home all year round. 

It Cuts Energy Costs 

A properly ventilated attic supports a strong roof system and can also help lower energy costs. Improving air circulation in the summer removes hot air, keeping your ductwork and inside air cooler. This allows colder air to flow through your HVAC system, preventing strain on your air conditioning and cutting cooling costs. 


Did you know that your roof system warranty terms will not cover damage caused by inadequate attic ventilation in whole or in part? Shingle manufacturers require that roof systems in which its shingles are installed meet industry or local building code standards for ventilation. That’s why it’s crucial to hire an industry leader with extensive training and licensing like National Contractors. Our team will install proper ventilation products tailored to the customer's roof style, architecture, and regional climate. 

Your new roof system is about much more than just its shingles. Full protection both outside and inside your home stems from proper ventilation, which helps reduce damaging moisture, lower the temperature in the attic space and decrease the risk of harmful ice dams. Ensuring your attic is properly ventilated helps extend the life of your roof, so it can take on any season for years to come. 

National Contractors has earned numerous manufacturer certifications and recognized among the top 2% of roofing contractors in North America with the GAF Master Elite® certification and included in the prestigious GAF President’s Club, the highest honor one can achieve. 

Ready to get started? We are happy to talk with you about your specific roofing needs and guide you through the entire process. As a GAF certified contractor, we offer superior protection with unmatched labor and material warranties. 

When you hire National Contractors, you’re getting the best in the business! Contact us today.

Image & Article Portions Courtesy of Wendy Helfenbaum and Karen Edwards, GAF 

Attic Ventilation