How do you calculate BTU/hr?

A British Thermal Unit (BTU) is used to measure thermal or heat energy and is the amount of energy needed to raise 1 pound of water 1°F at sea level. BTU/hr is measure of the thermal or heat energy generated per hour and is a measured to used specify air conditioners. The formula for calculating BTU/hr is: Heat Dissipation (Watts) x 3.4192 = BTU/Hr. So if a server has a heat dissipation (output) of 500 Watts the thermal or heat energy generated is 1709.6 BTU/hr.