How to measure an Air Conditioning equipment's efficiency?

Common Efficiency Standards

As there are various types of air conditioning equipment, there are a number of ways to measure efficiency of each. As they "diff'rent strokes for diff'rent folks". This is due to the fact that each type is used specifically for certain demands or limits of the designed application. 

air conditioning equipment

As defined by ASHRAE

• Coefficient of Performance (COP) - cooling: the ratio of the rate of heat removal to the rate of energy input, in consistent units, for a complete refrigerating system or some specific portion of that system under designated operating conditions. Higher COP means more efficient system.
• Energy Efficiency Ration (EER): the ratio of net cooling capacity in Btu/h to total rate of electricity input in watts under designated operating conditions. Higher EER means more efficient system.
• kW/ton: The term kW/ton is commonly used for larger commercial and industrial air-conditioning, heat pump and refrigeration systems. The term is defined as the ratio of energy consumption in kW to the rate of heat removal in tons at the rated condition. The lower thekW/ton the more efficient the system.

How to convert between kW/ton, COP and EER

• KW/ton = 12 / EER
• KW/ton = 12 / (COP x 3.412)
• COP = EER / 3.412
• COP = 12 / (KW/ton) / 3.412
• EER = 12 / KW/ton
• EER = COP x 3.412

If a chillers efficiency is rated at 1 KW/ton,

• COP = 3.5
• EER = 12

The major benefit of knowing the efficiency of air conditioning equipment in the market is the cost per consumption of power throughout the life cycle of the equipment. This greatly aids designers, installers and maintenance people in deciding what equipment is best suited for a certain application.