The nice thing about solar attic fans is that they draw energy from the sun, so you never have to wire them, and they are pretty much set and forget. Probably the biggest reason for solar attic fans is that they can help properly ventilate your attic, which can help cool down your home, and reduce the load on your HVAC system.
Even though solar attic fans aren't perfect, and every home is different, they can be beneficial for some homes that don't have adequate passive venting such as the 'gold standard' ridge and soffit vent system. In fact, if you install a solar attic fan (or any attic fan) with a home that already has ridge venting, it may conflict with your attic venting causing hot spots around the lower attic areas.
iLiving Hybrid 20-Watt
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QuietCool Gable 40-Watt
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Natural Light 48-Watt
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Solar RoofBlaster 3-Watt
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My Overall #1 Rated Pick
Updated On May 10, 2022
My overall top pick for the best solar attic fan goes to the iLiving Hybrid. This 20-watt solar attic fan has 7 individual fan blades to maximize airflow. The solar panel is also fully adjustable and tilts up to 45-degrees to maximize sunlight. The CFM or airflow rating is 1750, and it is suitable for attics up to 2,500-sf.
How Does It Work?
A solar attic fan is simply an attic fan that is powered by the sun.
Conventional solar attic fan are either plugged into a 120-volt outlet in the attic or hardwired into your home's power.
But with solar attic fans, they turn on automatically when the sun is out, and when the attic hits a particular temperature (if it comes with a thermostat). And when the sun goes down in the evening, the attic fan turns off.
Solar attic fans typically don't come with a thermostat but there are a few models that do.
Two Main Types
There are two main types of solar attic fans, gable mounted or roof mounted. Gable solar attic fans are installed on your gable vent in a vertical orientation, while it is connected to a solar panel on the roof through a cable.
Roof mounted solar attic fans are installed on the roof, and a circular hole is cut into the roof to install the fan.
How To Install?
The first step of installing a solar attic fan is to choose the location. Typically you want to install attic fans close to the ridge of the roof, about 2-3 feet from the top.
Placing your attic fan near the top is important because the hot attic air is rising to the ridge. In addition to near the ridge, ideally you want the solar fan on the southern side where you will be getting the most sun.
You also want the fan to stay away from any shade such as trees which can interfere with its operation. You may want to read my guide on installing solar powered attic fans for more details of each step.
What Is The Cost?
Attic fans themselves typically cost anywhere from $100 to $400, with an average around $200. It should take a roofer to install a single attic fan in the 2-3 hour range, and the labor cost will likely be $200 to $300.
I always recommend that homeowners get at least 3 estimates to install a solar attic fan, and if you can buy the fan unit yourself, the cost usually comes out cheaper.
Pros & Cons
Pro 1. Cooler Home
The most common reason to install a solar attic fan is to help cool down the home.
A hot attic is one of the biggest handicaps to a cool home, especially on the second level. If the attic gets very hot, this heat will radiate downwards towards the second and possibly first level of the home.
The HVAC system will run harder and more often to maintain its target temperature.
Pro 2. Protect The Roof
One little realized benefit of solar powered attic fans is that they can protect your asphalt roof from premature aging.
Typical roof shingles are made from an oil-derived product, and if this material gets very hot over and over, it can degrade. Attic fans can help prevent the roof from overheating and prematurely age.
Pro 3. Prevent Ice Damming
Ice damming is a phenomenon of homes in cold climates where the hot air from the interior of the home escapes into the attic.
The hot air melts the snow on the roof, and this water drips down and refreezes near the eaves --- forming an 'ice dam'. The ice dam will hold back more water until it starts dripping off the roof causing possible roof damage.
Con 1. Sucking Conditioned Air
This is probably one of the biggest downsides of attic fans. If your attic isn't properly insulated and air-sealed, or if you don't have enough soffit venting --- the attic fan may literally suck in the HVAC conditioned air from the interior and into the attic.
This may cool your attic, but you will be losing the benefits of cooling your home and reducing the HVAC load.
To help prevent this phenomenon, make sure you have enough intake vents in your attic for the CFM rating of the attic fan. It's a good idea to also make sure you don't have blocked soffit vents or even painted over soffit covers (it happens). Always remember: the air has to be supplied from somewhere, and if the attic fan can't get air from other intake attic vents, it will suck in air from the home interior.
If you have a newer home with an appropriately designed attics, it shouldn't require having an attic fan. But with older homes, it tends to be a different story.
Con 2. Vent Conflicts
If you install a solar attic fan in the wrong location, such as near a passive vent, they can conflict.
As an example, if you have a ridge vent, and you install a solar fan close to the ridge, the attic fan will be sucking in air from the ridge vent, and it will disrupt the passive air flow in the attic. If the attic fan disrupts the air flow from the soffit vents to the ridge vent, then you will get 'hot spots' lower down in the attic.
It is common practice not to install roof mounted attic fans (solar or conventional) if you have a ridge vent. If you want to learn more, you can read my full article on attic fans pros and cons here.
Sizing It Correctly
The easiest way to size a solar powered attic fan is to follow the manufacturer recommendations.
Almost all solar attic fans will have a stated maximum attic size which is usually in the 1000-sf to 2500-sf range. This is the floor area of the attic, which is usually the same floor area as the first or second level of the home. If your attic has a greater square footage, you will likely need to install two or more attic fans.
This 14-inch solar attic fan by iLiving is rated at 20-watts. The solar panel is adjustable from 0-degrees up to 45-degrees for maximizing solar absorption. In addition, you can have the option of adding an on/off switch as well as an power adapter kit to run it on household power (sold separate).
It comes with a 15-year warranty, and the brushless motor is waterproof with an ip68 rating. The iLiving attic fan is rated at 1750-cfm with a 2,500-sf venting capacity.
The built-in thermostat has a temperature range from 65-130F.
This attic fan by QuietCool is installed on your gable vent, and the 40-watt solar panel is fasted to your roof.
The nice thing about gable attic fans is that you don't need to cut a hole in your roof, and avoid any roof leaks. The DC motor is also quiet and very efficient, it also includes an AC/DC adapter so you can keep running it even when the sun goes down.
This gable attic fan has a solar panel that can be tilted up to 60-degrees as well.
This solar attic fan by Remington is rated at 20-watts and comes with a built-in solar panel. It is good for attics with up to 2000-sf, and it can move 1,280 cubic feet per minute of attic air.
This attic fan includes a variable speed motor which will increase or decrease speed based on the temperature. And unlike conventional attic fans, it comes with a thermostat and a humidistat so it can adjust based on temperature and moisture.
One cool add on (sold separate) for this model is a WiFi adapter that will allow you to control the attic fan through your phone.
Here is my most powerful solar attic fan pick --- it is made by Natural Light and it is 48-watts.
It is rated for attics up to around 2800-sf and it has a stated CFM capacity of 1,880.
The solar panel is adjustable so you can get the most sun, and it comes with a limited 25-year warranty.
You can also get a snap on thermostat which is sold separate.
The Remington 30-watt solar attic fan comes with an adjustable panel up to about 45-degrees.
It comes with a 24-38 volt DC variable speed motor so it will adjust the fan speed based on temperature. The variable speed motor also makes for a quieter attic fan.
This fan is rated for attics up to 2500-sf and it has a stated CFM capacity of 1970.
This Remington unit also comes with a free power adapter so you can have it on at night even without solar power (most other attic fans require an additional purchase).
Our budget-friendly pick solar attic fan is for smaller homes or RVs, and it is rated at 3-watts. This attic fan is rate for a roof of only 600 square feet, and rated at 39-cfm of air flow, you may need multiple for larger roofs.
The RoofBlaster comes with two ball bearings, and a black metal vent (not plastic). The motor is rated for 50,000 hours or 15 years, so it should last a while.
It also comes with a 1/8" mesh screen to prevent insect and pest intrusion.
This Broan-Nutone solar attic fan offers a one-piece aluminum 5-blade attic fan. It's housing has a molded design of UV-resistant ABS plastic that resists fading.
The 28-watt solar panel is integrated into the housing of the attic fan, and it is made of tempered glass which can withstand hail and other weather events.
It is rated at 537-cfm and it suitable for attics up to 3,200-sf. The big benefit of this Broan solar fan is that it is compact and low profile which can also make the install easier.