Does Attic Ventilation Work

Attic fans are intended to cool hot attics by drawing in cooler outside air from attic vents soffit and gable and pushing hot air to the outside.

Does attic ventilation work.

It promotes a cool dry attic. Static roof line vents are effective for ventilation but generally aren t recommended due to issues with leaks. Are ridge vents better. Your home s roof and attic was most likely designed with just the right amount of fresh air it needs.

Attic ventilation works on the principle that heated air naturally rises primarily utilizing two types of vents. Attics or roofs can be designed and constructed to be either vented or unvented in any hygro thermal zone map 1. It helps minimize the impact of ice damming. Most effective ventilation uses a ridge and soffit continuous ventilation system but even these designs can vary from roof to roof.

The model building codes allow both vented and unvented roof assemblies. 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. However if your attic has blocked soffit vents and is not well sealed from the rest of the house attic fans will suck cool conditioned air up out of the house and into the attic. Soffits gable vents without fans and rafter vents are passive ventilation systems to keep your roof and attic healthy.

Strong attic fans can actually back draft furnaces or water heaters by pulling combustion gases out of their burnersand into the home. The purpose of attic ventilation is so that heat can leave the attic when the air conditioner turns on and is trying to circulate cold air around the house. It helps prevent moisture from becoming trapped in insulation structural wood shingles and roof deck. When it is cold outside the ventilation system will work by maintaining the cold temperature so that ice will not melt on the roof and create ice dams.

Some may also argue that an attic fan helps in the ventilation of your roof and or attic. An attic fan works by drawing in cool air to the attic space that pushes out the hot air through vents. In such doing the attic fan will reduce the temperature in the attic space that in turn cools down the whole house. The attic fans are fitted with thermostats that will switch on and off the fan depending on the homeowner s preference.

Good attic ventilation is excellent for preventing moisture and condensation but it is usually not enough for cooling in the summertime. It allows outside air to flow naturally upward and out of attic. A retrofit example that works. Heat in the attic can roast shingles from below causing them to wear prematurely.

The choice of venting or not venting is a design and construction choice not a requirement determined by the physics or by the building code. Intake vents located at the lowest part of the roof under the eaves allow cool.