# Ceiling fan efficiency with 25-foot ceiling

| Posted in General Questions on

We are in the process of building a house with 12′ sidewalls and a vaulted ceiling. The ceiling height from the floor will be about 24′. The area below this fan will be 728 sq. ft.

A local salesperson stated that a ceiling fan (in a vaulted application) will not adequately move air even with a 72″ down rod. We were going to purchase a 68″ diameter fan.

I do not feel the person in the retail position may be giving the correct information. Any assistance would be greatly appreciated.

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### Replies

1. GBA Editor
| | #1

Jeff,
Here are the guidelines provided by a well-known manufacturer of large ceiling fans (Big Ass Fans):
The square footage of the space in which a fan is going should be 5-7 times the diameter of the fan. In other words, a 14-ft fan (measured from tip to tip at its widest point) would cover an area of at least 4,900 square feet. (That’s 5×14=70; 70×70=4,900.) The largest industrial ceiling fan made is 24 feet tip to tip; it would cover approximately 14,400 square feet. (24tx5=120×120=14,400.)
The fan tips must be 2 feet away from any ceiling obstructions or features, such as lights, trusses, beams or disco balls.
There should be enough distance between the ceiling and the fan that the fan doesn’t “suffocate” and has adequate space above it. This is generally 5-7 feet from the ceiling, depending on the fan’s diameter.
The fan should spin from 10 to 24 feet from the ground — often this recommendation is stated as the fan should spin its diameter above the floor.

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