Do I Need An Attic Exhaust Fan

Fresh air is pulled in from your soffits and or roof vent creating a draft through your attic.

Do i need an attic exhaust fan. Without exception you should talk to a professional to determine what your home requires. Attic ventilation works on the principle that heated air naturally rises primarily utilizing two types of vents. For both fans to work well they need large exhaust openings in the roof for the moving air to exit. As long as you have enough space at the base of the roof for an equal amount of soffit vents you shouldn t need a fan.

Ideally this will lower the high temperatures that have built up in your attic. 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. Whole house fans need windows and doors open and attic fans need lots of soffit vents to suck. Unlike a ventilation fan a whole house fan an attic mounted fan that exhausts air from a home at night is designed to cool a house that is to lower the indoor temperature.

Note that these two feet would not need to be one large opening. Ok i would definitely not recommend an attic fan. It is designed to lower the temperature of an attic by exhausting air from the attic and replacing attic air with outdoor air. Because what happens is attic fans are so strong that they actually reach down into the conditioned space of your house and they do that by using the wall cavities and where the outlets and pipes come through the walls as places where they draw air from the inside of your house it s that air conditioned air and it ll pull it right up into the attic and exhaust it outside.

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. It doesn t matter if the ventilation openings are spread out as long as there is sufficient space for all the air to escape. A powered attic ventilator has a different purpose. 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.

That said air resistance and interference such as vent grates reduces the area of true ventilation. This air is then exhausted through the fan to the outside. A fan might be necessary if the construction of your house is such that you. That means two feet of open space.