How to Determine the Right Size Ceiling Fan for a Room. Ceiling fans can drastically reduce the need for air conditioners in mild climates and significantly reduce their use in hot weather. Choosing the right size for a ceiling fan will optimally cool the room. Here's how to do it.
Measure your room's width and length in feet. Multiply the width by the length. This is your room's square footage.
Choose a fan with 26- to 36-inch blades for a room up to 75 square feet.
Choose a fan with 36- to 42-inch blades for a room from 76- to 144-square feet.
Choose a fan with 44-inch blades for a room from 144- to 225-square feet.
Choose a fan with 50- to 54-inch blades for a room over 225-square feet. Apply the ratios from there, or buy multiple fans using the same ratios. For instance, buy 2 fans with 44-inch blades for a 450-square foot room.
Choose a fan with standard mounts for typical 8-foot ceilings.
Choose a fan with extended mounts for 9- to 20-foot ceilings.
Choose a fan with flush mounts for ceilings under 8 feet.