How is the energy efficiency ratio (EER) calculated?

The energy efficiency ratio (EER) is an important metric used to measure the efficiency of cooling systems, such as air conditioning units. The correct calculation of EER is determined by dividing the cooling capacity of the unit, measured in British Thermal Units per hour (BTU/hr), by the power consumption of the unit, measured in watts (W). This ratio provides a direct insight into how much cooling is being produced for each watt of electricity consumed.

Choosing this particular formula highlights how effectively a cooling system converts electrical power into cooling output. A higher EER indicates a more efficient system, meaning it can provide more cooling with less energy consumption. Understanding this relationship is crucial for HVAC professionals when evaluating and recommending equipment based on energy efficiency standards.

In other options, while they involve components related to energy consumption, they do not correctly present the relationship defining EER as typically required in the industry. The focus on deriving the ratio by dividing cooling output by energy input captures the essence of energy efficiency in air conditioning systems accurately.