Zero-energy Attic Ventilation

Brett Freeman

If your attic is sweltering during the summer months, it's not getting enough ventilation, which is problematic for several reasons. First and foremost, the heat from a poorly ventilated attic, which can reach temperatures over 150 degrees Fahrenheit, can bleed into the rest of the house. Your air conditioning unit then works overtime to keep the house comfortable, which is a tremendous waste of energy, and your cooling costs are 25 percent higher than they should be, which is a tremendous waste of money.

The heat buildup also affects your roof's shingles, hastening the aging process and causing them to curl up or crack. During the cooler months, a poorly ventilated attic is prone to moisture buildup, which can cause wood rot in the roof and frame. An effective, efficient, and relatively inexpensive way to improve your attic's ventilation is to install solar-powered attic fans or wind-powered turbine vents.

Too Slow Air Flow
Most attic ventilation systems depend on the fact that heat rises. In theory, this hot air exits through vents at or near the top of your attic. As the hot air goes out, cooler air from outside is drawn in through soffit vents located at or near your attic floor. In theory, this process creates a continuous flow of air that keeps your attic relatively cool--100 degrees or so. But in many homes, this air flow is insufficient and attics become virtual ovens.

Solar, Wind, or Both?
If there is significant heat buildup in your attic, solar-powered attic fans and turbine vents are good options because they can significantly increase air flow, are relatively inexpensive and easy to install, and are powered by Mother Nature. Solar-powered fans have electric engines, but they draw their juice from solar panels. Turbine vents have rotors that are spun by the wind.

Determining which option is right for your home depends on your local climate. Turbine vents do allow hot air to escape whether their rotors are spinning or not, but they need at least a light breeze to truly be effective. If you live in an area that tends to have hot, still summers, turbine vents probably won't get the job done.

Solar-powered attic fans operate as long as their solar panels are getting direct sunlight, but at night and on cloudy days, they are out of commission. Because your attic can require several fans or vents to achieve adequate ventilation, a good strategy is to start by installing two or three turbine vents, which are less expensive and easier to install. If they seem to be functioning well, you can continue adding additional vents until you achieve adequate ventilation. If not, add a couple of solar-powered attic fans and re-evaluate. Because there is often more wind to drive turbine vents at night, when the solar-powered fans aren't working, a combination of the two will probably yield the best result.

About the Author
Brett Freeman is a freelance journalist. He also owns a landscaping and irrigation company in North Carolina. Previously he has worked as a beat reporter, a teacher, and for a home improvement company, and he used to own a bar/live music venue.

Search Improvement Project