These fans are designed to remove excess heat from your attic which in theory is supposed to lessen the load on the air conditioning in your home.
How much attic fan do i need.
Attic x 0 7 700 cfm minimum fan rating add an additional 20 cfm x 1 20 if you have a steep roof and 15 cfm x 1 15 for a dark roof.
Yet i still see the attic temperature reach 145 degrees.
Attic fans exhaust hot air from your attic to the outside.
All of that is in place.
Without exception you should talk to a professional to determine what your home requires.
How an attic fan works.
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.
Powered exhaust vents feature an electric or solar powered fan to create an effect similar to that of a turbine view example on amazon.
You need a minimum of 1 square foot of attic air venting for each 750 cfm of air flow.
Federal housing authority recommends a minimum of at least 1 square foot of attic ventilation evenly split between intake and exhaust for every 300 square feet of attic floor space.
Without this open space the fans will not move much air.
It might cost you approximately 300 600 for purchase and up to 550 when you include labor.
Attic vent fans are commonly rated from 800 to 1 600 cfm making one fans suitable for attics of up to around 2 200 square feet.
I had my attic floor sealed and a good amount of blown in insulation.
All you need to know about attic ventilation.
Whole house fans need windows and doors open and attic fans need lots of soffit vents to suck cooler outdoor air up into the hot attic.
That said air resistance and interference such as vent grates reduces the area of true ventilation.
Proper attic ventilation consists of a balance between air intake at your eaves soffits or fascias and air exhaust at or near your roof ridge.
When i last had a new roof installed a few years ago i calculated the soffit intake area i d need for the ridge vent specs.
Your soffit ventilation actually needs to be considerably more than 336 net square inches to supply a 700 cfm fan system or the fan is going to pull the air it needs through unsealed holes and gaps in the attic floor from the conditioned living space.
If you need 6 000 cfm of air flow through your house divide 6 000 by 750 to get a minimum 8 square feet of.
You might need to consider the following while installing an attic fan.
