Solar Powered
Attic Fan

What is it, and how does it work?

A "solar attic fan" is a power roof vent that runs on solar energy instead of electricity. Instead of consuming electricity to cool your attic, the solar fan uses a built-in solar panel to transform sunlight into electric power. This solar electric drives a motor that spins a fan blade and removes heat and moisture from your attic. The solar fan can be easily installed in less than an hour in most applications.

Solar attic fans save the homeowner money directly and indirectly. The roof receives direct, intense rays from the sun. Whether it's a shingled roof or a metal roof, heat begins building up in the attic space. Moisture also enters the attic space from daily activities such as bathing, cooking, laundry, etc. Unless this heat and moisture is removed, damage can occur in the form of mold, mildew, and dry rot.

When the attic space overheats, the shingled roof will heat on the underside of the shingles. This causes unnecessary wear and tear on your shingles and you risk wearing them out before the end of the warranty period. Shingle manufacturers are aware of this and require ventilation for a correctly installed roof to be covered under their warranty. This information can be found on the shingle package wrapper. Most shingle manufactures offer formulas on their web sites, which determine just how much attic ventilation is required.

Without adequate attic ventilation, the manufacturer may consider it an incorrect installation. What does this mean?

For example, imagine that you paid $4000.00 for the installation of a 25-year shingle. However, after 10 years it appears as though the corners are curled, and it's leaking. You contact the shingle manufacturer and complain of shingle failure. They examine the shingles under a microscope and determine that the excessive wear was from overheating caused by lack of adequate ventilation. Unfortunately, the warranty only covers correctly installed shingles, and yours were not. This results in another $4000.00 for a new roof, or your INDIRECT expense for inadequate attic ventilation.

Here's a quick check for attic overheating? Inside your home, get a stepladder and climb it - Be careful! Is the room warmer the further up you go? This is not a good sign. This means the air conditioner is working overtime to cool the inside of your home. The overheating in the attic space causes warming of your ceilings. That means more electricity usage than necessary, which results in higher electric bills. Thus, another INDIRECT expense!

Electric Attic Fans use about 350-400 watts of power per day when they run. These fans have thermostats that are set to start the fan when a certain temperature is reached, usually around 100 to 115 degrees. They will then run as long as it takes to get the temperature back down to 10 or 20 degrees below the starting temperature. The problem is this - once your attic is allowed to get to 100+ degrees (the starting temp of the electric fan) it will be a losing battle to cool the attic space, because this is happening during the hottest part of the day. Also, electric fans will consume $10-$20/mo. in energy costs just to run the fan. The DIRECT expense comes in winter when the temperature outside remains low and the thermostat doesn't cause the fan to run. As a result, the moisture remains in the attic with no place to go, causing ice dams, condensation, mildew, frost, and dry rot.

A correctly installed solar attic fan runs from sun-up to sundown, summer or winter, at no cost for operation. With air in the attic space constantly being circulated during the day, attic space temperatures remain lower. That means: 1) a cooler attic, 2) less work for your air conditioner, and 3) your shingles don't deteriorate before their life expectancy. Moisture escapes, and the risk of damage greatly decreases - thus preserving the integrity of one of your greatest investments ' your home. Ultimately this results in lower electric bills and money savings for the homeowner.

The cost of a solar attic fan will vary depending on the manufacturer, the roofer, and the area of the country. Usually under $600.00 including installation is a reasonable rate. Quality and correct installation are paramount. The solar fan with installation will generally cost less than the price of an electric fan. Properly installed, the solar fan will provide years of no-cost operation, while reducing energy consumption in your home. Because solar fans are low-voltage, there is no risk of fire.

As you can see, the benefits of solar attic ventilation are numerous, while making our world a cleaner and better place to live. Consider letting the sun cool your hot attic space and save you money!