PV Gap

Edna Said:

why don't houses use eletric fans to cool attics poosible solar power?

We Answered:

Lots of houses use aftermarket solar and conventional electric attic fans, and these products are widely available. These require prep work to make them really effective at keeping the attic cool. Plenty of soffit and/or gable vents are required to draw cooler air in while the attic fans are pulling hot air out the top. If the attic isn't ventilated well enough, the fans will be all but useless.

Solar attic fans have polysilicon photovoltaic cells that generate plenty of power to move several hundred CFM if your attic is well ventilated and if you have ample sunlight, preferably on a roof that slopes to the south or southwest. I have two of them rated at 1000CFM and they work great -- i save $75-$125 a month in electricity for air conditioning during the summer. Conventional electric (120VAC) attic fans are much cheaper if you are handy enough to wire them yourself. Hiring a separate electrician to do the wiring can be $$. The cost of the electricity used by an attic fan is minimal.

Most newer houses don't have attic fans unless you custom build, but they do have R40 or greater insulation to keep the house cool and plenty of soffit / ridge / gable vents to keep the attic ventilated. A homeowner can easily add (a) solar attic fan(s) on top of the roof if needed.