Roof ventilation is a critical part of a home.

Ventilation of the roof and attic space plays a critical role in helping a home maintain a consistent and ideal temperature for the roofing materials and also provide a buffer for the interior of the home. Vented attics with insulation on air-sealed flooring are one of the most important parts of a home system. However, if the installation of this system is done improperly, it could lead to many problems such as mold, energy loss, water leaks, and more.

While there are a variety of different kinds of ventilation styles, the theories depend on the climate.

For hot climates, ventilation helps to reduce the cooling load that the attic space bears from the heat of the sun, taking some of the strain off the air conditioning units. For cold climates, ventilation helps to keep the attic space cold in order to prevent ice dam formation. It also helps to vent moisture that has moved from the living space into the attic out to the exterior.

The various types of vents can be roughly separated into static, active, and power styles. Static vents have no moving parts and rely on the movement of air through the attic space through the process of convection. Active vents have moving parts that tend to rely on wind power. Power vents do use electricity and occasionally are regulated by temperature controls.

Static vents:


Box or turtle vents.

1. Often called box or turtle vents, these are a common type of ventilation system seen on a variety of roof configurations. Through the natural process of convection, these vents allow warm air to escape, most useful when the vent is installed as close as possible to the ridge of the roof. While these plastic or metal vents are cheap to purchase and install, multiple turtle vents are usually required in order to provide adequate ventilation.

2. Off ridge vents are often confused with box vents and they operate in a similar manner. These vents are longer and thinner than box vents and allow warm air to escape through a cut area of the roof. These also require multiple units to be installed for proper ventilation levels to be met.

Ridge vent along the ridge of this home.

3. Another type of static venting is the ridge vent. These vents are installed along the entire ridge of a home, providing consistent levels of ventilation. Unlike other venting styles that create hot and cold areas within the vented space, ridge vents keep the entire area at a consistent temperature. This helps to prevent the premature aging of areas of the roofing materials. These vents also operate independently from wind speed, providing ventilation regardless of outside weather patterns.

Soffit vents on this roof.

4. Soffit vents are a common and effective type of venting system that is seen on older and newer homes alike. These are installed in the soffits of a home and are often either aluminum or PVC. These are useful because they increase air flow by allowing air to enter from the lowest point in the roof.

Active vents:

1. Wind turbines, or whirlybirds, are often found in areas with consistent levels of wind, such as on the coast. These vents use wind power in order to pull warm air out of the vented space to the exterior. These vents tend to move more air than static box vents, but rely entirely on the consistency of wind speed.

Power vents:

A power vent installed on this roof.

1. Power vents use electric motors to drive a large fan that draws warm air out of the vented space. These can be thermostatically controlled, with a setting that turns the fan on when internal temperatures reach a certain level. These can also be fitted with a humidistat that activates the fan when internal humidity levels rise. One problem associated with these units is that while they do an excellent job of drawing warm air out of the vented space, they also draw conditioned air out of the living space through gaps in attic access hatches and recessed lighting. This can make it difficult and expensive to cool the home since the conditioned air is quickly pulled to the exterior by the fan.

With these different types of ventilation systems, which is the best type for your home? While no individual system is given the title as the best type of ventilator, the best system is generally thought to be a combination of ridge and soffit vents. By providing a continuous path for air to travel up from the soffits and out through the ridge vents, this system provides the most air movement, keeping your roof and attic consistent in temperature and low in moisture levels.