They have two basic models.
Balanced attic ventilation.
Figure 1 a balanced system.
Help protect your roof system from premature deterioration by installing a properly balanced attic ventilation system consisting of cobra exhaust vent at the ridge and adequate intake ventilation at or near the soffit areas of your roof.
Balance is the key.
Attic ventilation works on the principle that heated air naturally rises primarily utilizing two types of vents.
This method relies on convection which is a mode of heat transfer that is caused by the tendency of warmer air to rise.
In cold weather ventilation helps remove moist air from the attic that has migrated from the occupied living space reducing the risk of condensation in the attic.
That said air resistance and interference such as vent grates reduces the area of true ventilation.
Intake vents located at the lowest part of the roof under the eaves allow cool.
Another way to get balanced ventilation is to use the exhaust fans with controls and also install a supply fan.
Calculate or enter the square footage of the attic or area to be vented.
You can do this with a bath fan installed to blow air into the home or you can use a fan made specially for this task.
In other words the entire vent opening doesn t count as vented space.
Generally speaking you need a ratio of 1 300 where for every 300 square feet of ceiling space you need 1 square foot of attic ventilation.
I m thinking of the qufresh fan made by air king.
An under roof cathedral ceiling or attic ventilation system to help the building in any way needs to be properly designed and installed with adequate intake venting at the eaves outlet venting at the ridge and with careful sealing of air leaks from the occupied space into the attic or roof cavity to avoid heat losses or increases in both moisture movement into the roof cavity and increased heating or cooling costs.
To calculate the amount of ventilation you need for your home visit gaf s ventilation calculator now.
Proper attic ventilation can help reduce the load on your air conditioner.
The balanced attic consisted of electric power fans repositioned for maximum efficiency and air vent s new edge vent a shingle over intake vent.
The unbalanced attic consisted of a mix of ridge vents and electric power fans without intake ventilation.
The most common method is the static method.
Let owens corning roofing help you calculate exactly how much ventilation you will need for a healthy and balanced attic with our 4 step ventilation calculator.