Ventilation devices can be active or passive. Turbine vents are passive ventilation devices. Other examples of passive ventilation devices are the traditional metal pot vents and the popular ridge and soffit ventilation systems. Passive ventilation devices do not need electricity to work. Whereas, an active ventilation device could be an electric powered whole house fan or a powered roof ventilator.
Turbine vents consists of a turbine mounted on a sheet metal cylinder. They are normally installed like roof line vents along the face of the roof. When the wind blows, the turbine spins which draws air up out of the attic. Passive turbine vents need wind to be effective, but active turbine vents are not dependent on wind. Turbine vents are round metal vents with fins in them. They normally stick up from the roof surface to about 18 to 20 inches. The fins are actually located in a dome shaped structure that spins when the wind blows across it. The faster the wind, the faster the turbine will rotate. Turbine vents are effective in replacing the hot air in your attic within minutes. Wind blows across the fins in the roof turbine and it exhausts the heat build up.
The mechanics involved in the air movement is very simple. During warm weather, the air present inside the attic heats up and since warm air rises, it tends to rise up. When the turbines rotate, they suck the warm air out through the vent thereby bringing out a drop in temperature in the attic. Turbine vents have been vastly used for many years in residential, agricultural, commercial and industrial buildings. They are cheap and easy to install and can pump out vast amounts of air from the attic.
Let us consider a small 12 inch diameter turbine vent. When a constant wind speed of 5 miles per hour is blowing across its face, it can remove almost 350 cubic fee of air per minute. Even with the lack of any wind, the vents would still allow warm air to drift up and out of the attic. But the volume of air removed would be considerably lower. Though the statistics might not impress you much, it is proved that for a moderately sized home it will do just fine.
It is quite natural for people to think that the vents would leak during a rainstorm. Every rainstorm or even a rain shower is accompanied with wind, which will make the turbines spin, so that should blow off the raindrops off the vent. The same applies for snow too.
Roof turbine vents are cheap. The average cost of a high quality roof turbine would be about $50. Also the time taken to install one is just about 15…