Attic fan

Attic fans may be wired in several different ways. Usually, the fan is hardwired directly into an electric circuit, and is controlled by a thermostat most commonly ranging from to . It may also be hardwired but controlled by a switch. Another popular method is to have the fan plugged into an electric socket mounted nearby. An environmentally friendly method is to wire a specialized fan to a roof-mounted solar panel. Grounding/earthing Because an attic fan is made of metal, and is also subject to lightning strikes if mounted on a roof, grounding is extremely important. On some attic fans, grounding is achieved through a screw mounted on the thermostat box of the attic fan. The grounding wire is attached to the box via the screw and thereby grounds the external metal components. Most modern attic fans have this as well as a grounding wire connected directly to the motor, thereby ensuring all parts are grounded. ==Controversy==

Though every situation is different, there is some controversy about the effectiveness of attic fans. It has been theorized that in some cases the negative pressure that an attic fan produces in the attic can cause conditioned air from living spaces to be pulled into the attic through cracks and lighting fixtures. This loss of conditioned air can negate the energy conservation gains that might be expected from forced cooling of the attic with a fan. Fire danger In the event of a fire, an operating attic fan could, in theory, spread the flames because of the air movement. To reduce the danger, louvered vents that allow air to pass through can incorporate fusible links so that fire will melt the links in which case the vent will automatically close. In addition, an automatic cutoff switch can be set up to turn off power to the fan if it detects a temperature above a preset limit. ==References==