Attic Ventilation Theory

In a balanced ventilation configuration ambient outside air enters into the attic space via soffit or eave vents.

Attic ventilation theory.

More attic ventilation is good. The theory behind attic ventilation is to give that moisture a place to escape before it causes mold mildew rot or other problems. A thermostat is used to automatically turn the fan off and on while sometimes a manual switch is used. Ice dams form when a home s escaping heat warms the roof sheathing and melts the underside of the snow layer on the roof.

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. 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. 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.

While there are different product options available the process is typically done with a source of intake air fresh air normally drawn from the soffit or near the eaves and a source of exhaust typically near or at the roof s peak. In mixed climates ventilation serves either role depending on the season. Several purposes of an attic ventilation system are to provide added comfort to help protect against damage to materials and structure and to help reduce energy consumption during all four seasons of the year. 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.

Here are some of the myths and the facts you need to know about attic ventilation. An attic fan can be gable mounted or roof mounted. The problem with this design is it is wishful thinking. Attic ventilation works on the principle that heated air naturally rises primarily utilizing two types of vents.

Having attic ventilation doesn t ensure the moisture gets ventilated away before it condenses on your expensive roof and wall surfaces. 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. Intake vents located at the lowest part of the roof under the eaves allow cool. In simplest terms attic ventilation is a process of creating air movement and circulation in the attic space.