Page "Power (physics)" Paragraph 4

The dimension of power is energy divided by time.

The SI unit of power is the watt ( W ), which is equal to one joule per second.

Other units of power include ergs per second ( erg / s ), horsepower ( hp ), metric horsepower ( Pferdestärke ( PS ) or cheval vapeur, CV ), and foot-pounds per minute.

One horsepower is equivalent to 33, 000 foot-pounds per minute, or the power required to lift 550 pounds by one foot in one second, and is equivalent to about 746 watts.

Other units include dBm, a relative logarithmic measure with 1 milliwatt as reference ; ( food ) calories per hour ( often referred to as kilocalories per hour ); Btu per hour ( Btu / h ); and tons of refrigeration ( 12, 000 Btu / h ).