They have two basic models.
Balanced attic ventilation system.
A roof with a balanced ventilation system has an equal distribution of intake and exhaust vents 50 percent near the eaves and 50 percent near the ridge.
These systems do not significantly affect the pressure of the interior space with respect to outdoors.
During warmer months ventilation helps to keep attics cool thus a cooler living space.
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.
In most balanced ventilation systems heat and sometimes moisture are exchanged between the two airstreams reducing the heating and cooling loads caused by outside.
The balanced approach helps to optimize air exchange between the attic and the outdoors and allows for effective management of temperature and moisture inside the attic.
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.
No matter what month it is hot air will accumulate in the attic at the peak of the roof.
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.
That said air resistance and interference such as vent grates reduces the area of true ventilation.
The video explains how only a balanced system of both intake vents and exhaust vents can maximize the attic vents ability to help.
In summer and warmer months outside temperatures intensify the effects of this heated air.
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.
I m thinking of the qufresh fan made by air king.
To lower attic temperatures and to remove excess moisture.
A balanced ventilation system as opposed to supply only or exhaust only system has two fans.
Attic ventilation serves two main functions.
One bringing outside air into the building and the other exhausting stale interior air resulting in roughly balanced airflows.
Another way to get balanced ventilation is to use the exhaust fans with controls and also install a supply fan.
Lowering the temperature in the attic can help reduce air conditioning energy costs and roof deck temperature optimize the service life of a roof covering and minimize ice damming.
Roofing and attic ventilation systems are designed to work year round to balance the intake of cool air and the outflow of warm air in the home.
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.
