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.
Do we need an attic fan.
Powered attic ventilators or attic fans just as they sound are designed explicitly for placing or installing in the attics.
Often being situated on the roof attic fans are often in need of repairing or replacing following hail storms.
In a properly designed passive system air enters through the soffit.
Most homeowner s that are building homes and renovating older homes have found that a better choice for ventilating the attic space is through the use an attic fan.
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.
To reduce that expense some homeowners buy an electric or solar attic ventilator.
Soffits gable vents without fans and rafter vents are passive ventilation systems to keep your roof and attic healthy.
Some may also argue that an attic fan helps in the ventilation of your roof and or attic.
Ok i would definitely not recommend an attic fan.
Your home s roof and attic was most likely designed with just the right amount of fresh air it needs.
In other words the entire vent opening doesn t count as vented space.
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.
This fan moves 1 000 or more cubic feet of air per minute creating low pressure in your attic.
This prevents hot air from seeping into your home and driving up the temperature in the living space which reduces the load on your air conditioner.
The whole house fan and the more.
Electric attic fans however often increase energy consumption and cancel out any savings unless the attic is not insulated at all.
The ventilation that controls moisture from condensation and regulates the temperature in your attic relies on air circulation.
Pulling hot air out of the attic and cool air into the attic.
That said air resistance and interference such as vent grates reduces the area of true ventilation.
The main work of an attic fan is to regulate the heat level of the attic by removing hot air out of the attic and pushing it outside providing needed ventilation.
Attic ventilation fans help cool air your attic by pushing out the stifling hot air from inside the attic and bringing in cool air from outside.