These measurements are for general air flow requirements only. Decorating plans or aesthetic considerations may also influence your fan choices beyond these room size specifications. For very large rooms, multiple fans is an option.

*Blade Sweep =  The diameter of the circle you see when the fan blades are in motion. Or, the measurement from the tip of one fan blade to the tip of the blade directly across.

 Approximate Room Size

Blade Sweep 

40 - 60 sq. ft. 26" - 42"
70 - 90 sq. ft. 44"
100 - 150 sq. ft.

52" - 54"

Over 160 sq. ft.
12' - 15' (Great Room)

60" - 99"


Be sure there is at least 7 ft. of clearance under your ceiling fan blades. A standard 6" downrod should work in most 8 ft. ceiling installations. This positions the blades far enough from the ceiling to have enough "supply" air above the blades to provide good air movement. If greater floor to fan clearance is needed, some fans can use a low ceiling adapter without using any downrod. 

*This chart shows recommended downrod lengths for various ceiling heights.

Ceiling Height Downrod Length
9' 12" 
10 18"
12' 24"
14' 36"
16' 48"
18' 60"
20 72"