What is the most preferred unit of measure for cooling capacity?

Cooling capacity is the measure of a cooling system’s ability to remove heat from a space. The most preferred unit of measure for cooling capacity is watt (W), which is the SI unit for power. Watt is defined as the amount of energy transferred or converted per unit time. One watt is equal to one joule of energy per second. Using watt as the unit of measure for cooling capacity allows for easy comparison and calculation of the cooling performance and efficiency of different cooling systems.

Other units of measure for cooling capacity are ton, BTU, and horsepower, but they are less common and less convenient than watt. Ton is a unit of measure that describes how much water at freezing temperature can be frozen in 24 hours, equivalent to 3.5 kW or 12,000 BTU/h. BTU (British Thermal Unit) is a unit of measure that describes the amount of heat required to raise the temperature of one pound of water by one degree Fahrenheit, equivalent to 0.293 W. Horsepower is a unit of measure that describes the rate at which work is done, equivalent to 746 W.