Ceiling fans work to increase air movement in a room, which can make warm or humid spaces more comfortable and reduce both heating and cooling costs. Ceiling fans may also provide lighting and improve the aesthetics of a room.
In warm weather, a ceiling fan can make a room feel 4 or 5 degrees cooler than the ambient temperature. In cool weather, a fan's rotation can be reversed to force warm air downward and around the room. Since warm air moves upward and gathers at ceilings, this helps distribute the warmth more evenly. Ceiling fans are required to meet stringent airflow- and energy-efficiency standards to be rated ENERGY STAR compliant. Ceiling fans with lighting components must meet separate requirements for ENERGY STAR lighting compliance.
Ceiling fans are one of the few safe options for cooling outdoor spaces, such as decks and outdoor kitchens, and semi-outdoor rooms such as sun rooms and enclosed patios. Ceiling fans with built-in lighting fixtures provide light to these areas, and the moving air created by the fans helps repel insects.
Although new ceiling fans are generally very quiet, older fans may become noisy. Ceiling fans may also be difficult to clean and maintain, as they are usually mounted on the highest structure of a room.