In low-wind situations, turbine vents do an admirable job of drawing warm air out of the attic areas of a property. However, when the wind blows, these vents become a powerful vacuum of hot air, drawing it through the ventilation grille just as effectively as any other electrical alternative. Turbine fans use only the wind that blows to the outside to turn. These fans are usually installed along or near the peak of the roof, which is called a ridge.
Turbine fans have angled slots cut into a capped cylinder, which create a continuous fan blade. The wind turns the fan blades, causing air movement in the attic as the air exits through the turbine and is replaced by outside air. Turbine fans have no more power than wind, so when the wind doesn't blow, the turbine doesn't turn. Roof turbines are a more economical alternative to attic ventilation.
They can work as an “active roof vent” when the wind blows, or there is excellent static pressure in your attic, but most hot months in Texas don't promote the turn and performance of a roof turbine. It is important that these “roof eye sores rotate” so that they create the CFM or “cubic foot per minute” airflow they need to change the temperature of the attic. The concept behind wind turbine ventilation grilles is that the rotating blades will help expel air from the attic. Warm air rises naturally, so if the attic air is heated above ambient temperature, a vent will allow the less dense warm air to escape.
Commercial uses of wind ventilation turbines often connect very large fans to the bottom and are used to extract things like smoke from a building. A domestic ventilation turbine does not have this fan. A problem that is often cited with typical ventilation grilles is that they stop the rise of this warm air with the inverted V that is located at the top of the vent. The Federal Housing Authority recommends at least 1 square foot of attic ventilation for every 300 square feet of attic floor space, with half of the ventilation at the bottom of the attic entry holes and the other half in the top exhaust vents.
While this fan may not move as much air, it can provide adequate ventilation for an attic with up to 300 square feet of floor space. Electric, solar and wind vents use powerful fans and turbines that blow warm air out of the attic space while drawing cooler air through the louvers around the ceiling panels. The Lomanco Whirlybird fan uses wind energy to spin your turbine and remove harmful heat and moisture from the attic. A solar fan is not dependent on the wind and, in fact, has a more powerful motor, so it keeps the attic temperature regulated regardless of wind conditions.
This 1,000 CFM galvanized steel electric fan can pump enough hot and humid air to keep attics up to 1,600 square feet cool.