Frequently Asked Questions
What is a solar attic fan?
A solar attic fan is an active ventilation system that is typically installed on the roof of an attic. These types of fans use solar panels to collect energy from the sun to propel fan blades, which provide constant air flow to an attic space.
Solar attic fans also help extract excessive heat and moisture in an attic. This helps protect your roof and insulation systems, while providing added comfort to the home.
How to size a solar attic fan?
To determine what size solar attic fan(s) you need for your attic, you first need to know the size of your attic in square feet.
To determine the size of your attic, multiply the width by the length of the attic floor in feet. For a single story house, this is usually the same as the square footage of the house itself.
Next, multiply the square feet of attic space by 0.7 to get the minimum number of cubic feet of air per minute that the fan should be rated to move. Example: 1,000 sq. ft. attic x 0.7 = 700 CFM minimum fan rating
Add an additional 20% (CFM x 1.20) if you have a steep roof, and 15% (CFM x 1.15) for a dark roof. Attic fans come in all different shapes and sizes. Be sure to check the CFM rating of the product that you are interested in prior to installation to determine how many you need.
What is CFM?
CFM, or Cubic Feet per Minute, determines the amount of air that a fan can move while operating at the highest speed. The larger the attic, the higher the CFM must be in order to efficiently cool that space. CFM for attic fans is a critical measurement for sizing and installation.
What is the best solar attic fan?
The best solar attic fans are typically Made in the USA and come with a minimum of a 25-year warranty. Our choice for the best solar attic fan is the Solaro Aire (pictured on this page). We are a certified distributor of Solaro’s products, and based on our experience, we have found them to be the best solar attic fan for ventilation performance, durability, and aesthetics. To see how Solaro compares against other fans on the market, check out our detailed solar attic fan reviews guide.
Is there a tax credit for solar attic fans?
Solar powered attic fans are eligible for a 26% Federal Tax Credit on the purchase price of the fan, installation and sales tax. Additional incentives may be available through certain State, municipalities, and utility companies.
Do solar attic fans work on cloudy days?
Yes. Ordinary daylight is all that’s required. As long as the product is placed so that the solar panel is not obscured by hedges or under a roof overhang, it will gather sunlight and transform it into DC power.
Are solar fans worth it?
Solar fans are worth the cost of materials and installation because they can provide year-long benefits across multiple climates. Most people think of the primary benefits being with cooling and energy savings from the summer months. These benefits can be heightened in more hot and humid climates. But there are also a number of other benefits that solar fans provide in cooler environments and during the winter. Constant airflow and ventilation can help remove excessive heat build up and moisture, which can damage insulation and structural elements of your home, such as your roof. Read our post on Do Attic Fans Really Work for more information.
Where should I place my solar attic fan?
Ideally, you want to put your solar attic fan on a south or west facing slope. Aim to put your fans on a central or “middle” portion of your roof. Keep in mind that you want to draw cooler outside air from a soffit (or gable) and flow that through your attic. Make sure to keep your fans approximately 5 feet away from ridge vents (or other open vents).
How to tell if your solar attic fan is working?
Most quality solar powered attic fans are whisper quiet in operation. This is an attractive feature for homeowners, but can also open up the question on whether or not it’s even working. The best way to tell if your solar attic fan is working is to go up into the attic and inspect it yourself during the day. Your attic should feel cool and comfortable (close to the outside temperature) when you enter it. You should also be able to see the fan blades rotating. As always, please use proper safety precautions when entering your attic. If you need assistance, it’s best to request an attic inspection to check your fan to make sure it’s running properly.
How long can I expect a solar powered attic fan to last?
The lifespan of a solar attic fan will depend on the product and manufacturer. The best solar fans typically come with a 25 year, or limited lifetime warranty. These are a number of cheaper solar fans on the market that last on average for 3-5 years. Replacing a cheap solar fan every few years however becomes cost prohibitive. We would recommend buying and installing a fan with a better warranty for savings and peace of mind.