Attic Ventilation Theory

Insufficient ventilation can lead to moisture problems during the winter and decreased energy efficiency during the summer but too much ventilation can be just as bad if not worse.

Attic ventilation theory.

In simplest terms attic ventilation is a process of creating air movement and circulation in the attic space. In a balanced ventilation configuration ambient outside air enters into the attic space via soffit or eave vents. An attic fan can be gable mounted or roof mounted. Here are some of the myths and the facts you need to know about attic ventilation.

Attic ventilation works on the principle that heated air naturally rises primarily utilizing two types of vents. Ice dams form when a home s escaping heat warms the roof sheathing and melts the underside of the snow layer on the roof. In mixed climates ventilation serves either role depending on the season. Having attic ventilation doesn t ensure the moisture gets ventilated away before it condenses on your expensive roof and wall surfaces.

Another important element of attic ventilation is protection for the roof s shingle. The theory behind attic ventilation is to give that moisture a place to escape before it causes mold mildew rot or other problems. Just like properly sizing your furnace and air conditioning unit you want precisely the right amount of attic ventilation for your home. A powered attic ventilator or attic fan is a ventilation fan which regulates the heat level of a building s attic by exhausting hot air.

Intake vents located at the lowest part of the roof under the eaves allow cool. This air passes through the attic space where it displaces warm moisture laden air which in turn exits the attic via vents at or near the top of the space being vented. More attic ventilation is good. Heat in the attic can roast shingles from below causing them to wear prematurely.

It s believed that good ventilation in the attic will help prolong the life of shingles by reducing heat which maintains the shingles quality and durability. The intent of roof venting varies depending on climate but it is the same if you re venting the entire attic or if you re venting only the roof deck. In a hot climate the primary purpose of ventilation is to expel solar heated hot air from the attic or roof to reduce the building s cooling load and to relieve the strain on air conditioning systems. The problem with this design is it is wishful thinking.