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Are Solar Attic Fans Worth It?

Posted July 27, 2022 by Patrick Morin
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Is your attic hot, damp, and/or musty smelling? These are tell-tale signs of poor air circulation, which can create extra wear and tear on your attic and roof.

If you live in Portland, you aren’t alone in your struggle with musty attics. Portland is among the least air-conditioned cities in the U.S., along with Seattle.

Attic fans can improve airflow for homes with or without HVAC systems. Some homes opt for solar attic fans over electric, but you may be asking, “Do solar attic fans work in all homes? Are solar attic fans worth it?”

The answer depends on many factors. We have all the information you need to navigate attic fans and Portland’s unique climate.

How Do Solar Vents Work?

Solar-powered attic fans cool spaces similar to natural and mechanical vents. All attic fan types vent the hot and muggy air from your attic and bring cooler, fresher air in from outside.

This venting process reduces your energy bills and issues like dampness and mold. If your attic consistently struggles with poor air circulation, a proper attic fan can extend the lifespan of your insulation and roof.

Power source is the main difference between solar attic fans and traditional fans. Attic fans can be powered by:

  • Electricity
  • Natural airflow
  • Wind turbines
  • Sunlight

Solar fans use direct sunlight for their spinning energy. Without enough solar energy conversion, however, these fans do not work. You’re still stuck with a hot attic at night or on cloudy days. 

Do Solar Attic Fans Work Everywhere?

A solar attic vent relies on direct sunlight for power, so it can be difficult to get the most from its use. Indirect sunlight won’t be enough to fire up the fan blades.

There are many factors that affect solar power effectiveness:

  • Hours of sunlight per day
  • Sunny days per year
  • Latitude location
  • Roof orientation
  • Roof angle
  • Proximity of trees, buildings, and other sunlight blockers
  • Power efficiency requirements

Residential solar systems often work around these limitations by using tilt arrays and/or increasing the number of panels. These are not cost-effective options for solar-powered attic fans, however.

Are Solar Attics Fans Worth It?

An attic solar fan needs perfect conditions for a good ROI. Your investment in home improvements is a balance of expenses vs recouped costs, which can vary with certain factors.

Solar power systems are much more expensive for upfront costs, including installation. People who opt for solar power usually hope to see an ROI from long-term energy savings.

Without these energy savings, a solar attic vent is more costly and less efficient than traditional attic fans. A solar-powered fan would need to perform as regularly and as productively as a traditional attic fan to be worth the money. 

Why Solar Attic Vents Aren’t Worth Your Money in Portland

Unfortunately, this means Portland sees little benefit from solar attic fans. Portland has three strikes against solar power efficiency:

  • Latitude
  • Peak sunlight per day
  • Sunny days per year

Additionally, if your solar fan isn’t spinning due to cloudy or rainy weather, you can’t install a different system as a backup. Experts and installation instructions routinely warn against mixing ventilation systems, which create more airflow problems than it solves.


In the Northern Hemisphere, sunlight’s impact angle decreases the farther north you travel. This means direct sunlight in northern latitudes is less intense than direct sunlight by the equator.

If a large panel doesn’t generate enough energy, covering your roof with solar panels for one small attic fan system will quickly negate your cost-to-benefit ratio, if it’s even an option.

Peak Sunlight per Day

Solar power relies on a certain amount of peak sunlight per day. This refers to the hours per day when sunlight becomes intense enough to convert solar energy into power.

Oregon ranks slightly better than more northern states like New York and Washington. They still come out #41 in all 50 states, however, with only 4.03 hours of peak sunlight.

By contrast, even Wyoming (6.06) and South Dakota (5.32) rank higher for peak sunlight at similar latitudes. This means Portland homes need many more solar panels to generate electricity, significantly increasing the cost of any solar energy system.  

Sunny Days per Year

Along with peak sunlight hours, solar energy needs enough sunny days per year to be worth your money. Even a slight cloud cover can reduce power generation.

Did you know Portland actually has fewer sunny days on average than even Seattle? Portland only gets around 144 days of annual sunshine, compared to Seattle’s 152. Your solar-powered attic fan will only work 39% of the year, and won’t work at all during the night.   

Alternatives to Solar Ventilation

Of course, you can still have roof and attic ventilation in Portland without having to opt for a less than practical solar fan. But you still don’t have to suffer hot and musty attics full of mold.

Traditional attic fans circulate air more effectively than a solar attic vent, which has variable power. They also offer other benefits over solar:

  • Less expensive installation costs
  • Works during any weather
  • Works at night
  • Fewer ROI woes
  • Greater thermostat control

There are two types of fans that work well in Portland: natural vent and mechanical vent. Both systems can cool your attic consistently and efficiently.

Natural air flow vents increase your home’s existing air circulation. They cost very little to install and don’t add any electricity costs to your energy bill.

If your home doesn’t get much natural airflow, you can use mechanical vents powered by electricity. These units are relatively cheap compared to solar attic fans. They work in all weather conditions and at all hours.

Traditional vents are also easy to maintain. Even an electric attic fan can go years between basic maintenance check-ups. 

A Fresh Clean Attic Is Just a Quick Call Away!

Now you know the answers to, “Do solar attic fans work?” and “Are solar attic fans worth it?” for your home. Although solar fans work well in sunshine states like Arizona, they have certain power needs that aren’t always practical in places like Portland.

If you’re looking for premium attic ventilation services from local area experts, we can help! Contact us for a free quote today.

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