Building Science Attic Fans

Even solar attic fans can cause problems.

Building science attic fans.

Trying to solve the heat gain problem in your attic by using a fan is like lying out at the beach with a fan blowing over you and thinking you re not going to get a sunburn. Most moisture gets into an attic via air movement not by diffusing through materials we want to keep the living space and the nonhabitable attic space at the same moisture conditions says armin rudd of building science corp. A powered attic ventilator has a different purpose. Building science fundamentals see all events a building science consulting and full service architecture firm specializing in building technology for all types of buildings including commercial institutional and residential.

The remington solar ventilation attic fan is completely the remington solar ventilation attic fan is completely powered by free solar energy. Don t let your attic suck power attic ventilators are a bad idea. Intake vents located at the lowest part of the roof under the eaves allow cool. Much of that heat then conducts downward and finds its way into the house.

This american designed fan is designed to reduce attic temperatures and remove destructive moisture thus making your home more comfortable and reducing the load on your hvac system and lowering your electricity bills. I am trying very hard to simply accept the science from an expert in this case. Attic air conditioner and furnace standard vented combustion gas furnace with a single stage air conditioner located in a south texas attic. Using fans to ventilate your attic violates the fundamentals of building science.

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. Using a fan to blow hot air out of the attic doesn t address the radiant heat flow from the roof to the attic floor. Attic ventilation works on the principle that heated air naturally rises primarily utilizing two types of vents. And we didn t make it easy to get into the attic.

However as a very old builder 70 years i have known cases where roof mounted attic fans have helped tremendously where the roof is a full hip and the ratio of ridge vents to soffit vents was way out of whack. The amount of attic cavity ventilation is specified by numerous ratios of free vent area to insulated ceiling area ranging from 1 150 to 1 600 depending on which building code is consulted the 1 300 ratio being the most common. In westfield mass who helped write the new code language.