Modern Ceiling Fans

The flush mount ceiling fan is mounted flush to the ceiling while the hanging ceiling fan will have some combination of bars, chains and wires between the fan and the ceiling.

Mounting heights for the flush mount ceiling fan
The advantage of flush mount ceiling fans is that they can provide much of the air circulation that a hanging fan provides without taking up as much space.

Ideally, the blades of a household ceiling fan should be at least 24 inches (609 mm) from the ceiling to allow for maximum, unrestricted airflow. However, this is usually not possible for the modern ceiling fan in most homes. Since blades should be at least 7 feet (213 cm) above the floor, keeping the ideal distance between the ceiling and the fan blades would require a ceiling height of 9 feet (274 cm) or more.

However, while 24 inches (609 mm) is ideal, it is not required for the ceiling fan to provide a nice airflow. While a hanging ceiling fan should be used for higher ceilings, a flush mount ceiling fan works just fine for most homes.

Maximizing air flow
To get the best airflow with the flush mount ceiling fan, it is best to look at the blade surface area. While more blade surface area means better airflow to a point, too much surface area does not allow enough air to be drawn up between the blades and reduces airflow. Therefore, a four bladed fan will produce more airflow than a five bladed for the same speed in most situations.

Blade pitch is also very important. The greater the pitch (angle the blades are turned) the more airflow they will produce. Since greater pitch requires more power to turn the blades, cheaper fans and motors have lower pitches (usually between 9 and 13 degrees). More expensive fans will have stronger motors and pitches into the 20s.

Motor speed or RPM is another major factor in airflow. Greater RPM will increase airflow but will require a larger motor and more power if the size and pitch of the blades are kept constant. Thus, a balance between power consumption and desired cooling effect should be found.

When buying a flush mount ceiling fan or a hanging one, keep these points in mind when balancing desired airflow and price.