There are many ventilation options that may be implemented in an attic space, including mechanical and non-mechanical ventilation, such as ridge, gable, soffit and roof vents.
Mechanical vents are wired, electronically operated vents that may be used as either intake or exhaust vents. Both types are necessary to ensure that the attic is properly ventilated. The direction of the vent's rotor will determine whether it will bring cool air into the attic or send warmer air outside. Mechanical vents must be powered on to work and do not require much energy. However, these vents may be noisy.
Gable, ridge, soffit and roof vents are all types of non-mechanical vents. Gable, ridge and roof vents are used for exhausting hot air. Gable vents are positioned underneath the apex of the attic roof, which may allow hot air to rise above the vent and escape it. Gable vents may be motorized. Ridge vents run along the entire ridge of the roof and provide the most exhaust ventilation due to the fact that they prevent hot air from becoming trapped in the attic.
Roof vents are dome or square-shaped and are installed on the roof. These vents are generally used for exhaust, although they may be used for intake as well. Soffit vents are placed along the length of the underside of the attic overhang and allow cool air to constantly flow through the attic.