Manufacturer recommendations help homeowners select appropriate fan sizes. Homeowners determine the blade span of a fan by measuring from the tip of a blade to the center of the fan, then doubling this number. The square footage of the room is the length of the room multiplied by the width. The fan's retail box has the manufacturer's recommended ceiling-fan sizes for owners to check their measurements.
In addition to the size of the fan, another important factor to consider is the distance from the bottom of the fan to the floor. Enough space should be maintained to allow for safety when walking underneath the fan, usually 7 feet, and for maximum air distribution. Most manufacturers include a hanging rod with the fan. This rod is usually adequate for average-height ceilings. Flush-mount models can be purchased for rooms with low ceilings. Rooms with high ceilings require the purchase of an extension rod. These rods range in length from 12 to 72 inches.
The outlet box must support the ceiling-fan's weight and may require additional support if the fan weighs more than 35 pounds. Mounting systems or support braces can be purchased from the manufacturer of the ceiling fan to ensure compatibility.