One potential problem would be sucking moist moldy air up from the crawl space intothe house.
Energyvanguard power attic.
This is most often done with spray polyurethane foam spf insulation either open cell or closed cell.
Power attic ventilators banned by new georgia energy code.
Whether you re a home or business owner we can help.
Attic power ventilators are simply not worth the cost and effort.
Power attic ventilators can cause problems even without air conditioning.
Now we don t have to settle for a technology that pulls conditioned air up from the house.
These are real problems from real houses that have really happened.
Energy vanguard this powered attic ventilator in a gable wall was one of eight in that attic.
Powered attic ventilators are the worst way to try to keep your attic cool.
These attic fans can move a lot of air through an attic but that doesn t have much effect on the radiant heat flow.
A better way to reduce the attic temperature is to go after the source the radiation constantly blasting the attic from the bottom of the roof deck and rafters.
Another would be backdrafting a water heater and putting carbon monoxide in the house.
The new energy code that went into effect in georgia this year dealt a body blow to the power attic ventilator industry.
Gable vents ridge vents turtlebacks and whirlybirds.
And it s part of the reason that my state georgia has banned power attic ventilators unless they re solar powered which was a concession needed to get the grid powered fans banned.
That s one reason power attic ventilators aren t a good solution.
They re going after the air but the air is hot only because all the solid materials are hot.
There s a new boss in town.
They ve been well discussed here and other places but briefly they re not cost effective don t deal with the problem where it starts are using convection to solve a radiant heat problem and can even be dangerous by backdrafting combustion appliances and putting carbon monoxide in the home.
In fact the home power article states that a typical 250 watt fan would use 180 kwh per month if run continuously.
Energy vanguard is your source for home performance training consulting hvac design and more.
For decades concerned homeowners have looked for ways to keep their attics cool.
Then they moved from passive to active and latched onto the powered attic ventilator.
Only one type is allowed.
Here in the southeastern us open cell is most often the spray foam of choice.
Sources such as the billings gazette energy vanguard and home power all have articles that essentially say the same thing.
