The enclosed space of an attic can get very warm; to move hot air from this space attic ventilation fans are often used. Fans in the attic can also be of benefit if the attic is moist, this will be particularly noticeable during hot, humid weather. Although it is not possible everywhere in the country, where the conditions are ideal an attic ventilation fan can cool the entire house, eliminating the need to run the central air conditioner on a steady basis.
There are three types of attic ventilation fans that are in common use. The first type uses no electric power; it simply uses the power of the wind to rotate the turbine blades. This type of fan is of little or no value in those parts of the country where windy days are a rarity. Although these turbine style fans need wind to make them run at their most efficient, the heat in the attic tends to make the blades turn enough to expel at least some of the hot air from the space.
The two other popular types of attic ventilation fans run on electric power. These types of fans are normally controlled by a simple switch, either off or on but there are more sophisticated models that are variable speed. Another feature which is often found on more costly models is a switch that is activated by a thermostat; the power to the fan comes on once the attic temperature hits a predetermined upper limit.
In the last few years attic vent fans which are solar powered have become increasingly popular. These solar powered units have a distinct advantage over wired units as they operate without having to store the energy. Although this is a distinct advantage when the sun is out, they are less than efficient when the weather is overcast and there is little or no direct sunlight. There are solar powered models available that come with a storage battery; this fan can operate regardless of whether it is day or night. This type of fan is often used in homes located in areas with tropical temperatures.
The primary objective of an attic fan is to eliminate heat from the space; however they also eliminate moisture which is the cause of mold. This is extremely important when the home is in an area of the country where humidity levels tend to be elevated during the heat of the summer.
5 people like this post.