Ceiling fan be used to reduce the stratification of warm air in a room by forcing it down to affect both occupants' sensations and thermostat readings, thereby improving climate control energy efficiency. Punkah-type ceiling fans date back to 500 BC, and are native to India. Unlike modern rotary fans, these punkah fans move air by moving to and fro, and were operated manually by cord. The first rotary ceiling fans appeared in the early 1860s and 1870s in the United States. At that time, they were not powered by any form of electric motor. Instead, a stream of running water was used,
Ceiling fan cause damage to the fan. Building codes throughout the United States also prohibit industrial ceiling fans from being mounted with the blades closer than 10 feet from the floor for these reasons. In 2004, "MythBusters" tested the idea that a ceiling fan is capable of decapitation if an individual was to stick his or her neck into a running fan. Two versions of the myth were tested, with the first being the "jumping kid", involving a kid jumping up and down on a bed, jumping too high and entering the fan from below and the second being the "lover's leap",