When the exhaust fan is switched on, the blades that are inside are turned which helps in extracting all of the hot air that has accumulated. The blades are the ones that come in contact with the incoming air as they pass through the ducts.
Depending on the size of the incoming air, the blades are placed either horizontally or vertically. By positioning the blades in a vertical direction, it would bring the air to the bottom of the duct. The horizontal arrangement of the blades will have them running across the entire length of the duct.
The main purpose of a fan blade is to ensure that the incoming air is directed to the engine. Since the exhaust air enters the duct from the top, the bottom half of the fan blade would be placed to direct the flow of air downwards.
The type of fan blade is also important. It is the variable speed which allows the blades to be turned and regulate airflow. This is why it is important that the blades are inspected before the installation.
As soon as the blades have been made, they are matched up with the turbine condition. Once they are matched up, the control panel is placed in front of the fan and all the blades are turned accordingly.
Depending on the wind conditions, the blades will be directed either downwards or sideways. This will be beneficial to remove all of the condensed air, thus leaving room for more air to enter.
A fan with wind speed rating is best for areas where there is a tendency of high winds. The speed rating will tell you how fast the blades are turning and will allow the flow of air into the duct.
Some areas which have low-speed ratings may require that the blades are turned slightly faster in order to remove all of the condensed air. This is due to the fact that the blades are spinning slightly slower in comparison to other areas.
The fan blades that are located between the duct and the house is called the flex. This is to accommodate areas that need to be cooled but does not have the wind to blow against the house.
When the ducts are opened and the doors move downwards, it creates a vortex that will send the air into the house. The intake fans which run underneath the house make use of this same principle to extract the air from the house.
The noise level is another factor that can be altered with the installation of these types of fans. A noise level of one is perfect for homes that are below 20 feet, but a high noise level of two is the norm for houses that are above that.
There is also special equipment to be considered when installing this exhaust fan. These include heat sinks, belts, strainers, cooling coils, filters, blowers, clamps, etc.