Metric horsepower (PS, Pferdestärke) equals approximately 735.5 watts, slightly less than imperial horsepower, and is the standard power unit for vehicle ratings throughout Europe and Asia. Car specifications in Germany, Japan, and China typically list engine output in PS. One PS equals about 0.9863 imperial horsepower or 0.7355 kilowatts.

BTU per hour (BTU/h) equals approximately 0.293 watts, the standard rating unit for air conditioners, heaters, and furnaces in North America. A typical window air conditioner rated at 10,000 BTU/h can cool a 400–500 square foot room, making this unit essential for HVAC system sizing. One BTU/h equals about 0.2931 watts.