If you've ever wondered if there's a difference between attic or roof ventilation, or tried to compare solar attic fans and rooftop turbines, we can help you! There is a difference, and it can make a huge difference in the performance of your home. There is a difference and it can make a huge difference in the performance of your home.
The problem with turbines
Roof turbines are an inexpensive alternative to attic ventilation. They can function like "active" roof vents when the wind blows, or have a good static pressure in your attic, but most hot months don't promote the rotation and performance of a roof turbine. Importantly, these "eyelets in the roof" actually spin, so they create the CFM or "cubic feet per minute" of airflow they need to change your attic temperature.
Why We Recommend Solar Fans
Solar fans don't need any electricity, wind or attic pressure to spin. The sun can do that! A solar fan can actively pull more air into your attic than a turbine. A solar fan is not wind dependent and it actually has a more powerful motor so it keeps your attic temperature regulated regardless of wind conditions. Solar fans are truly "active roof ventilation" and can lower your attic temperature by up to 25 degrees. .... , and we might add that they also look a little better on your roof.
Why you shouldn't mix ventilation systems
We often see an attic with multiple types of roof ventilation. In most cases, this is ineffective because the ridge vents will compete with the solar fan or the roof turbine will weaken the ridge vents. You should not use a mix of active and passive ventilation systems. Also, if you decide to add or change your attic ventilation, active roof vents should not be within 10-20 feet of passive vents.
Air is like water or electricity, it will take the path of least resistance. We want air to be sucked up through your gable vents: the vents right under the eaves of your house. These vents allow air to flow into your attic. If you install a turbine next to your ridge vents, the turbines will not pull air from the eave vents into your attic. Instead, they may try to circulate air back and forth between each other. This does not ventilate the attic.
What if we already have a ridge vent or turbine?
If you already have a ridge vent on your roof and you want to add a solar fan, we will likely block off the inside of the ridge vent. The vent would still be there, but we would block the air flow so that the solar fan would pull in air from your ridge vent. Most likely, when adding a solar fan, we'll want to replace the existing passive vents or roof turbines. We will look to block any other roof vents within 10-20 feet to prevent "air circulation" at the roof level.