How to Vent an Attic

When you think about the overall health of your home, you probably don’t think about your attic. But you should, as the ventilation in your attic can have a big impact on your home. A poorly ventilated attic space can lead to higher energy bills and costly home insurance claims. If you’re wondering how to properly vent your attic, we’ve got the answers.

Why attic ventilation is important

Your attic’s ventilation system allows your house to breathe by recycling the air in your attic. Basically, it pulls fresh air into the attic through intake vents, then pushes out the trapped air through exhaust vents on the roof.

A well-ventilated attic space is crucial for maintaining a healthy and energy-efficient home. Here’s a more detailed explanation of why attic ventilation is so important:

Reduced Heat and Energy Bills

A poorly ventilated attic can trap heat in the summer months, causing your home to overheat. This increased heat can strain your HVAC system, leading to higher energy bills. By venting the attic, you can reduce the amount of heat that enters your home, helping your air conditioner work more efficiently and potentially lowering energy bills.

Longer-Lasting Roof

Heat trapped in an attic—especially during the hot weather—can deteriorate roofing materials, such as asphalt shingles. Moisture buildup can also warp the plywood in your attic. Both of these things can lead to roof leaks and costly repairs. Proper attic ventilation will help push the warm, moist air out of your attic, keeping your roof in good condition.

Moisture and Mold Prevention

If an attic becomes hot and humid, especially during the summer, it can lead to condensation on cooler surfaces like insulation. This is the perfect recipe for mold and mildew to grow, which can be harmful to your home and your health. Excess moisture can also lead to wood rot. Fortunately, a good attic ventilation system will allow this moisture to escape.

Ice Dam Prevention

Ice dams usually form after a heavy snowfall followed by a period of freezing temperatures. Basically, warm air inside your home reaches your attic and heats up the underside of the roof. The warmed-up roof then causes the snow and ice on it to melt. Houses with good attic ventilation are less likely to experience ice dams, because good airflow helps keep the temperature of the roof’s underside cold. This helps prevent the snow on the roof from melting.

Signs of poor attic ventilation

An attic space with poor ventilation can damage your home in a number of different ways. Fortunately, you can prevent the damage before it happens—as long as you know what to look for. Here are some telltale signs that your attic might have a ventilation issue:

Higher-Than-Normal Energy Bills

If your attic is poorly ventilated, your air conditioning system has to work harder and less efficiently to keep your home cool, especially during the hotter months. This could result in elevated energy bills.

Excessive Heat Buildup

Check to see if your upstairs rooms are uncomfortably hot during the summer months. Without proper attic ventilation, heat from your attic could radiate down through the ceiling and into those living spaces below.

Ice Dams

An ice dam forms when warm air from the attic melts the snow on your roof from underneath, only for the water to refreeze by the roof’s edge. Proper attic ventilation helps to avoid this ice buildup by maintaining a consistent roof temperature.

Sagging Roof

Another sign of poor attic ventilation can be a sagging or discolored roof. This happens over time, as the excess moisture created by poor attic ventilation seeps into your roof’s wood decking.

Damaged Shingles

Trapped attic heat can burn your roof to the point that asphalt shingles crack or curl. It’s also possible that the adhesive can deteriorate, leading to shingles sliding off your roof.

Mold and Mildew

The humidity in a poorly ventilated attic is the ideal environment for mold and mildew. If there’s mold growth in your attic, you may notice a musty odor upstairs or when your air conditioner is running.

Termite Infestation

Termites thrive in hot, moist environments. If you find termites in your attic, it’s probably because your attic isn’t pushing out the trapped air through exhaust vents.

Types of ventilation systems

There are two distinct categories of attic ventilation systems: active and passive. Both systems are designed to draw outside fresh air into your attic and then expel your attic’s hot air and dampness.

Active Ventilation

As its name implies, active ventilation actively moves air in and out of your attic. It does this through the use of electrical power. These powered vents and fans can be installed directly into your homes electrical system or plugged into an outlet. They can also come with thermostats that turn on when the attic reaches a certain temperature.

Common active roof vents that you can install include electrical vents, solar-powered vents, turbine vents and ridge vents with a baffle.

Passive Ventilation

Attics with passive ventilation rely on natural forces, such as the wind, to circulate the air. Because these systems don’t rely on electricity, they are silent and require minimal upkeep. With no reliance on home electricity, they can also bring down utility costs over time.

Common passive roof vents that you can install include gable end vents, box vents, soffit vents, cupola vents and ridge vents without a baffle.

Choosing the right vent for your roof

Proper airflow in your attic is a vital part of maintaining a functional and healthy home. It is essential to preventing mold growth, ice dams and other potential issues. With so many roof vent options available, it can be difficult to know which one is best for you.

It’s important to remember that every house is unique. As a result, a certain ventilation system for one home may not be right for another. Usually, the type and shape of your roof will determine which solution you should install—active or passive. Both types of attic ventilation systems can do the job. It’s just a matter of choosing the right one.

If you’re not sure how to vent an attic, try consulting with a certified vent installer or building inspector. Hiring a certified vent installer also ensures that your home is in compliance with local building codes, which can reduce insurance complications in the future.