Gable vents are used to help provide ventilation to attic spaces. Unlike other attic vent types, gable vents are designed to be seen, and they add a decorative touch to a home.
Gable vents are installed near the peak of a roof in an area known as the gable. Gable vents come in a variety of shapes, including round, square or triangular, and they generally have louvers to help keep rain out. Many gable vents have a screen or netting to prevent insects and small animals from entering the attic space. Most gable vents are passive and simply allow air to enter and exit the attic naturally. However, this doesn’t provide the best air circulation.
Attic spaces trap air and moisture, which causes mildew and mold to form. Air trapped in attics is often extremely hot and can be a fire hazard. Gable vents allow this air to escape to prevent fires and moisture. If wind is working with the vents, then the vent is effective. When there is an absence of wind or it is blowing in the opposite direction, the vents are not as effective. In 2015, building codes and standards are stricter than in the past, so some older homes may not have gable vents.
Air near the vents circulates, but warm air still accumulates near the peak of the roof. Powered fans are often used to help move the air, but by themselves, gable vents still aren’t the most effective way to vent an attic. They work best when paired with other vents, such as soffit vents, which are installed underneath the eaves of the roof. This allows air to enter through the lower section of the attic and then flow up and out through the gable vents, improving ventilation. However, if a ridge vent is installed along with soffit vents, the gable vents should be closed off to avoid short-circuiting the air flow.