For example, this table shows that 1 kilowatt-hour (kWh) = 3413 British Thermal Units (Btu). If you were to convert 15 kWh to Btu, use the following calculation:
15 kWh x 3413 British Thermal Units = 51,195 Btu 1 kWh
For example, this table shows that 1 watt = 0.001341 horsepower. If you were to convert 250 watts to horsepower, use the following calculation:
250 watts x 0.001341 horsepower = 0.34 horsepower 1 watt