Install a Ceiling Fan – Lowe’s Home Improvement …

Fan blades must be mounted at least 7 feet above the floor. For maximum efficiency, they shouldn't have any obstruction within 24 inches of the blade tips.

An appropriate junction or outlet box securely attached to the building structure is required. Replace the old box with one labeled as approved for ceiling fans or ceiling-suspended paddle fan installation. The box and its support must be able to support the moving weight of the fan. Use the installation hardware recommended by the junction box manufacturer. Fans over 35 pounds, with or without accessories, require additional support independent of the outlet box.

Secure the new box to a brace between ceiling joists. If there isn't a 2-by-4 wood brace between the joists but you have access to the framing through the attic, add a brace.

Otherwise, install an expandable metal ceiling-fan hanger bar. These may be positioned either from the attic or from below the ceiling, through the rough opening. Secure the box to the bracket with a U-bolt.

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Install a Ceiling Fan - Lowe's Home Improvement ...