Are Solar Attic Fans Worth It?

By Kami Turky


Solar attic fans have gained popularity in recent years as homeowners search for eco-friendly and cost-effective ways to keep their homes cool during the sweltering summer months. 

But the real question is, are solar attic fans worth the investment? 

In short, the answer is yes. They will save you the hassle of dealing with skyrocketing energy bills, frequent air conditioning maintenance, and potential damage to your home’s structure due to heat and moisture buildup.

In this article, I will delve into the worthy aspects of solar attic fans, exploring their numerous benefits, including cost-effectiveness, eco-friendliness, and their role in protecting your home’s structure and insulation. 

Key Takeaways

  • Attic fans are designed to maintain proper air circulation and temperature in the attic
  • Solar attic fans use solar energy to power a fan that expels hot, humid air and brings in cooler, fresh air from outside
  • Solar attic fans are worth the investment because they are cost-effective, eco-friendly, and protect the roof from damage
  • Solar attic fans reduce air conditioning usage and eliminate operating costs, promoting energy savings
  • Solar attic fans utilize renewable energy, improve indoor air quality, and contribute to sustainable energy practices
  • Solar attic fans prevent roof damage by maintaining a consistent attic temperature, minimizing ice dams, and reducing mold and mildew growth
  • Potential disadvantages of solar attic fans include the possibility of pulling air from inside the home if the attic is not well-sealed, the risk of roof leaks if not installed and maintained correctly, and potential issues with blocked soffits in older homes

What Are Attic Fans?

Attic fans are ventilation systems specifically designed to maintain proper air circulation and temperature in your attic space. 

They work by drawing hot, humid air out of the attic and allowing cooler, fresh air to enter through vents or soffits. 

This process helps to prevent heat build-up and excessive moisture in the attic, contributing to a more comfortable living environment and protecting your home from potential damage. 

There are 2 types of attic fans depending on how you can mount them:

  • Roof-Mounted Attic Fans: These fans are installed directly on the roof of your home, typically near the ridge. They are designed to blend seamlessly with your roof’s aesthetic and are available in various styles and materials to match your home’s exterior
  • Gable-Mounted Attic Fans: Gable-mounted attic fans are installed on the gable end of a house, behind an existing gable vent, or with a new vent opening. They are often easier to install and maintain than roof-mounted fans, as they do not require cutting into the roof itself

How Do Solar Attic Fans Work?

Solar attic fans work by harnessing solar energy to power a fan that circulates air through the attic, expelling hot, humid air and drawing in cooler, fresh air from outside.

A solar attic fan consists of a solar panel, a fan motor, fan blades, and a control system that includes a thermostat. 

The solar panel is typically mounted on the top of the fan unit or in a separate location, depending on the design. 

This panel contains photovoltaic (PV) cells, which are made of semiconductor materials like silicon. 

When sunlight hits the PV cells, electrons within the semiconductor material are excited, creating an electric current. 

This current is then used to power the fan motor and ultimately drive the fan blades.

The fan motor in a solar attic fan is a direct current (DC) motor, which is highly efficient and can operate at variable speeds based on the amount of sunlight available. 

As a result, the fan will run faster when there is more sunlight, providing more effective ventilation during the hottest parts of the day.

The control system in a solar attic fan monitors the temperature and humidity levels in the attic, activating the fan when certain thresholds are reached. 

When the attic temperature or humidity rises above the set level, the control system triggers the fan to begin drawing hot, humid air out of the attic through the exhaust vent. 

This process creates negative pressure within the attic, which then draws cooler, fresh air into the attic through vents or soffits.

Why Are Solar Attic Fans Worth It?

1. A Cost-Effective Way to Cool Your Home

One of the primary benefits of solar attic fans is the reduction in air conditioning usage. 

Solar attic fans work by removing hot air from the attic, reducing the overall temperature within the space. 

As a result, your air conditioning system doesn’t have to work as hard to cool the entire house. 

By easing the burden on your air conditioner, you can save on energy bills, as the system consumes less electricity. 

For example, a study by the Florida Solar Energy Center found that proper attic ventilation can reduce air conditioning energy consumption by up to 30%.

In addition to reduced energy consumption, solar attic fans have no operating costs. 

Since they are powered by solar energy, they do not require any external electricity to function. 

This eliminates the need for additional electrical wiring and ongoing energy costs associated with operating the fan. 

To illustrate, a traditional electric attic fan may cost between $50 and $150 per year in electricity, depending on the size of the fan and the local energy rates. 

In contrast, a solar attic fan has zero energy costs since it relies solely on sunlight to function.

Finally, installing a solar attic fan can increase the resale value of your home. 

Prospective buyers may be more inclined to choose a house with a solar attic fan, as it offers energy savings, a more comfortable living environment, and environmental benefits. 

In a survey conducted by the National Association of Realtors, 63% of respondents said they would be more likely to consider a home with energy-efficient features, such as solar attic fans.

2. An Eco-Friendly Way to Stay Cool During Summer

One of the main advantages of solar attic fans is their utilization of renewable energy. 

Unlike traditional electric fans, which require electricity generated from fossil fuels, solar attic fans rely solely on sunlight, a clean and abundant energy source. 

So, by opting for a solar attic fan, you actively contribute to reducing greenhouse gas emissions and promoting sustainable energy practices. 

Solar attic fans also contribute to improved indoor air quality. 

By promoting better ventilation in the attic, these fans help reduce the concentration of indoor air pollutants such as mold, mildew, and volatile organic compounds (VOCs).

3. They Decrease the Possibility of Damage to Your Roof

One common issue that solar attic fans help prevent is the warping and deterioration of roof decking. 

High attic temperatures can cause the roof decking to expand, contract, and eventually warp. 

Solar attic fans play a vital role in maintaining a more consistent attic temperature, which prevents these issues from occurring.

They work by expelling hot air and promoting proper airflow within the attic. 

By doing so, they reduce the overall temperature and prevent heat buildup, which can cause the roof decking materials to warp over time. 

Another problem that solar attic fans address is the formation of ice dams in colder climates. 

Ice dams form when snow on the roof melts and then refreezes at the eaves, causing water to back up under the shingles and potentially leading to leaks or water damage. 

In this case, the solar attic fans work by regulating attic temperatures and ensuring proper air circulation, which maintains a consistent attic temperature that is closer to the outdoor temperature. 

By doing so, they minimize the temperature differences between the attic and the exterior, reducing the chances of snow melting and refreezing at the eaves. 

Solar attic fans also contribute to the prevention of mold and mildew growth in your attic. 

Excess moisture can lead to mold and mildew, which can not only damage your roof’s structural components but also pose health risks to your household. 

By promoting proper ventilation and reducing humidity, solar attic fans help prevent mold and mildew growth, protecting both your roof and your family’s health.

What Are the Disadvantages of Solar Attic Fans?

1. Attic Fans Can Pull Air from Inside the Home

One potential disadvantage of solar attic fans is that they can pull air from inside the home if the attic is not well-sealed. 

This occurs when the solar attic fan creates negative pressure in the attic space, causing it to draw in conditioned air from the living space below through gaps, cracks, and other openings. 

This unintended airflow can lead to increased energy consumption for heating and cooling, as the HVAC system needs to work harder to maintain a comfortable temperature within the home.

To better understand this phenomenon, consider the fact that solar attic fans work by expelling hot air from the attic, creating a vacuum that needs to be filled with cooler air from the outside. 

Ideally, this cooler air should enter the attic through soffit vents, ridge vents, or other passive ventilation systems. 

However, if these vents are blocked or the attic is poorly sealed, the fan may end up drawing air from the living spaces below instead.

In order to prevent this issue, you should ensure that their attic is well-sealed, with particular attention given to the sealing of attic access points, such as hatchways, pull-down stairs, or any gaps and cracks in the attic floor. 

Additionally, ensure that the home’s passive ventilation system is functioning properly, with soffit vents and ridge vents clear and unobstructed.

By addressing these potential issues, you can minimize the likelihood of their solar attic fan pulling conditioned air from inside the home, allowing the fan to work efficiently.

2. Solar Attic Fans May Cause Roof Leaks

Like any other roofing penetration, such as vents, skylights, or chimneys, solar attic fans require the correct installation methods and materials to ensure a watertight seal and prevent water intrusion.

One of the primary concerns when installing a solar attic fan is ensuring that the flashing and sealing around the fan are done correctly. 

Flashing is a thin material, usually made of metal, that is installed around the fan to direct water away from the penetration and onto the roof surface. 

It is crucial that the flashing is appropriately fitted, secured, and sealed to prevent water from seeping in around the edges of the fan.

In addition to flashing, you should use high-quality sealants to create a watertight seal between the solar attic fan and the roofing material. 

This is particularly important in areas with harsh weather conditions or heavy rainfall, where even small gaps can lead to significant water damage over time.

Furthermore, proper maintenance of the solar attic fan is essential to reduce the risk of roof leaks. 

This may include periodic inspections of the flashing and sealant, as well as ensuring that the fan itself is functioning correctly and free from debris or damage that may affect its performance.

To mitigate the risk of roof leaks caused by solar attic fans, I recommend you hire a reputable installer with experience in solar attic fan installations. 

By choosing a skilled professional, you can ensure that their solar attic fan is installed correctly and safely, with a minimized risk of future leaks and water damage.

3. Older Homes Have Blocked Soffits

In older homes, one issue that may affect the performance of solar attic fans is the presence of blocked soffits. 

Soffits are the underside of a roof’s overhang, and they often contain vents to facilitate the intake of fresh outdoor air into the attic. 

This airflow is essential for maintaining proper ventilation and ensuring that solar attic fans can effectively expel hot air from the attic space.

However, in some older homes, soffit vents may become blocked by insulation, debris, or even nesting animals, which can hinder the flow of air into the attic. 

As a result, the solar attic fan may struggle to draw in sufficient fresh air, limiting its ability to cool the attic and provide the desired energy-saving benefits.

To address this issue, it’s crucial for homeowners to inspect their soffit vents and ensure that they are clear and functioning correctly. 

This may involve removing any insulation that has been inadvertently pushed into the vents or cleaning out debris, such as leaves or bird nests, that may have accumulated over time.

In some cases, older homes may have insufficient or improperly designed soffit venting, which can also impede attic ventilation. 

In such instances, it may be necessary to consult with a professional to assess the home’s ventilation needs and determine the best course of action for improving soffit venting.


What Are the Disadvantages of Solar Attic Fans?

Disadvantages of solar attic fans are potential air leakage from the home, risk of roof leaks, and issues with blocked soffits in older homes.

How Much Does a Solar Attic Fan Reduce Temperature?

A solar attic fan can reduce attic temperatures by up to 40 degrees Fahrenheit, depending on the fan’s capacity and the local climate.

How Long Does Solar Attic Fan Last?

Solar attic fans typically last for up to 20 years, with the solar panel and motor being the primary factors determining their lifespan.

Why Get a Solar Attic Fan?

Getting a solar attic fan is beneficial for lowering attic temperatures, reducing energy costs, and extending the life of your roof and insulation.


As promised, we’ve covered the many benefits and potential drawbacks of solar attic fans from their energy-saving capabilities to the concerns of air leakage and roof leaks. 

We have explored how they can make a difference in your home’s comfort, energy consumption, and overall sustainability. 

And if you ask me, I’d recommend you turn all your home appliances solar-powered for more sustainable and efficient living

I hope this article was helpful and if you still have any questions, feel free to leave a comment below.

Kami Turky

Kami is a solar engineer with nearly a decade of experience in researching, testing, and reviewing various solar products. He has also provided technical consultation to several organizations on the best ways to incorporate solar energy into their operations. When he’s not busy helping others find the best solar solutions, Kami enjoys spending time outdoors, hiking, camping, and exploring the natural wonders of his home state.

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