Experts agree that for every 300 square feet of attic space, at least 1 square foot of ventilation is necessary. This is especially true in hot climates, where the primary purpose of attic or roof ventilation is to expel hot, sun-heated air from the attic in order to reduce the cooling load on the building. Field monitoring has confirmed that an unventilated roof will be a few degrees hotter than one that is well-ventilated. In climate zones other than 6 or higher, it is not necessary or recommended to control steam on the inner assembly side of the attic.
To avoid costly repairs and replacements, it is important to ensure that the attic is properly insulated and ventilated from the start. Attic ventilation works by keeping roof temperatures cool all year round and expelling moisture from the conditioned attic space. According to the U. S.
Federal Housing Authority, for every 300 square feet of attic space, at least 1 square foot of ventilation should be installed, divided equally between exhaust pipe and intake. In cold climates, the main objective of attic or roof ventilation is to maintain a cool roof temperature to control ice accumulations created by melting snow and to ventilate moisture that passes from the conditioned space to the attic. If gable ventilation grilles or ceilings are not possible, it is important to install entrance grilles at the bottom of the roof. Beam-shaped ventilation grilles, or insulating baffles, can be installed in the attic beam space and create narrow gaps that direct fresh air from the ceiling vents to the top of the roof.
Vapor barriers can be installed in attic sets with ventilation in climate zones 6 or higher, but should be avoided in other climate zones as condensation on top can occur during periods of air conditioning. To facilitate this exchange of hot and cold air, it is recommended to install at least 1 square foot of ventilation for every 300 square feet of attic floor. In winter, proper insulation and attic ventilation can control ice accumulations by allowing snow to melt evenly on the roof. Attic ventilation is essential for maintaining a comfortable temperature in your home and preventing costly repairs due to moisture damage. In hot climates, proper ventilation helps reduce cooling costs by expelling hot air from your attic.
In cold climates, it helps prevent ice accumulations on your roof and ventilates moisture from your conditioned space. For optimal results, experts recommend installing at least 1 square foot of ventilation for every 300 square feet of attic floor.
