Changes

* ''Length of the fan's blades''. The longer a fan's blades are, the larger percentage of a room's air volume upon which the fan will have a relevant impact. This factor is of greater importance in large rooms. The majority of ceiling fans come in one of three sizes (sweep diameter): 36", 42", or 52".

* ''Length of the fan's blades''. The longer a fan's blades are, the larger percentage of a room's air volume upon which the fan will have a relevant impact. This factor is of greater importance in large rooms. The majority of ceiling fans come in one of three sizes (sweep diameter): 36", 42", or 52".

* ''Total surface area of the fan's blades''. The greater a blade's surface area, the more air it is able to move. However, there can be "too much" surface area (refer to ''Blade surface area to air-feed ratio'' below).

* ''Total surface area of the fan's blades''. The greater a blade's surface area, the more air it is able to move. However, there can be "too much" surface area (refer to ''Blade surface area to air-feed ratio'' below).

* ''Pitch of the fan's blades''. The angle at which the fan's blades are tilted relative to the [[Cartesian coordinate system#In three dimensions|X-axis]] is referred to as the "blade pitch". The steeper (greater) the pitch, the greater the airflow. Since increased pitch also means increased [[Drag (physics)|drag]], only fans with well-made motors can support steep pitches. Cheaply-made fans typically have a pitch between 9 and 13 degrees. A pitch of 15 degrees and upwards is considered very good, with numbers in the 20s being the highest.

* ''Pitch of the fan's blades''. The angle at which the fan's blades are tilted relative to the [[X-axis]] is referred to as the "blade pitch". The steeper (greater) the pitch, the greater the airflow. Since increased pitch also means increased [[Drag (physics)|drag]], only fans with well-made motors can support steep pitches. Cheaply-made fans typically have a pitch between 9 and 13 degrees. A pitch of 15 degrees and upwards is considered very good, with numbers in the 20s being the highest.

* ''Speed of rotation''. The speed at which a fan rotates, measured in [[Revolutions per minute|RPM]] (Revolutions Per Minute), directly correlates to the amount of air moved. Faster rotation equals greater airflow.

* ''Speed of rotation''. The speed at which a fan rotates, measured in [[Revolutions per minute|RPM]] (Revolutions Per Minute), directly correlates to the amount of air moved. Faster rotation equals greater airflow.

* ''Blade surface area to air-feed ratio''. In general, more blade surface area means greater airflow. However, if there is too much blade surface area, there will not be adequate space between the blades for air to be drawn through. Fans which have an unusually large blade surface area, such as fans with decorative palm-leaf-style blades or many fans with six blades, do not have adequate space between the blades for an unrestricted amount of air to be drawn through. This results in reduced airflow. The effect of this ranges from negligible to dramatic, depending on the exact dimensions involved. Contrary to popular belief, more blades typically does ''not'' equal more airflow. Most four-bladed fans move more air than comparable five-bladed fans spinning at the same speed; this is indeed noticeable on five-bladed fans which have an option to install only four of the blades. Also due to this effect, the overwhelmingly vast majority of industrial fans have three blades.

* ''Blade surface area to air-feed ratio''. In general, more blade surface area means greater airflow. However, if there is too much blade surface area, there will not be adequate space between the blades for air to be drawn through. Fans which have an unusually large blade surface area, such as fans with decorative palm-leaf-style blades or many fans with six blades, do not have adequate space between the blades for an unrestricted amount of air to be drawn through. This results in reduced airflow. The effect of this ranges from negligible to dramatic, depending on the exact dimensions involved. Contrary to popular belief, more blades typically does ''not'' equal more airflow. Most four-bladed fans move more air than comparable five-bladed fans spinning at the same speed; this is indeed noticeable on five-bladed fans which have an option to install only four of the blades. Also due to this effect, the overwhelmingly vast majority of industrial fans have three blades.