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How Solar Attic Fans Help Cool Down Your Electricity Bill

Example Of A Solar Powered Attic Fan

Keeping It Cool

Solar powered attic fans are not a new idea. In fact they have been on the market for nearly twenty years. Not until recently, as an "economy of scale" has reduced prices, have they become affordable for the average homeowner.

The beauty of solar powered attic fans is that they reduce your home cooling cost in the summer by removing hot air that adds to your home's heat gain and they use no outside electricity in the process. After all, any truly "green" device that saves energy should not need to use any electricity to do so.

Improvements In Solar Attic Fan Motor Design, Brushless Motors

Brushless DC Motor As Used In a Solar Roof Vent

Solar attic fans and solar gable fans use a small photovoltaic panel, usually ten watts, to drive a brushless, long life motor.

Brushless motors have fewer moving parts and do not wear out in the same way that a traditional motor does. Because of this newer solar attic fans can last for years and years with no maintenance.

 The bearing assembly is sealed and there is no  oiling or other maintenance.  Solar attic fans normally move about 800 cubic feet of air per minute when the sun is shining directly on the photovoltaic panel.

How Many Solar Roof Vents Do You Need?

You should think of solar roof vents and solar gable vents as part of a holistic approach to venting your attic. Your primary source of ventilation should be passive air flow, up through vents along the eaves and out the ridge vents and gable vent. A continuous ridge vent is better than a dozen solar attic fans but a solar attic fan can boost air flow. For a typical ranch style home of 2500 square feet four solar roof vents, combined with adequate ventilation should be enough.

Types Of Solar Powered Roof Vents and Attic Fans

You can buy either a gable mounted solar attic vent, which you install at the end of your roof overhang or a model that sits directly on the roof and requires a hole of approximately a foot and a half in diameter. Rooftop solar attic ventilators are best installed by a professional but an experienced do it yourselfer can do the job in about three hours.

If you have a typical shingle roof it involves peeling back a couple rows of shingles, cutting a hole using a paper template that comes with the vent, screwing the vent base down to the wood deck and replacing and tarring the shingles and then placing the solar roof vent onto the base and aiming the solar panel to the recommended angle.  

Solar attic fans or solar roof vents usually come with enough electric cord to mount them up to six feet from the vent if you need to place the panel in an area that gets more sun.

Getting hot air out of the attic is a very good way to lower your electric bills in summer. A hot attic could be costing you as much as fifty percent of your cooling costs. When your attic cooler less heat is radiated down through the ceiling and your air conditioner has to work less. Even if you have a well insulated attic if it is poorly ventilated and therefore extremely hot, some of this heat will make it down through the insulation into your home.

Good Air Flow Is Important For Solar Roof Vents To Work Properly

In order to work properly solar attic fans need to have good ventilation along the eaves of your home to allow  cool air to flow in and be sucked out by the fan.

It is also a good idea to check your insulation since a well ventilated and well insulated attic go hand in hand when it comes to saving on cooling bills. If you do blow in insulation, install inexpensive foam blocks to keep the insulation from piling up and blocking air flow.

When you install a solar attic fan or solar gable vent, make sure that there is room for air to flow up and over attic insulation. Don't place fiberglass batts all the way up against the end of the rafter or blow in cellulose insulation to a point that it piles up and restricts air flow.  If you found this site helpful, please "like us" on Facebook, etc, or forward it to your friends here: