A higher Coefficient of Performance (COP) indicates better efficiency. For most chillers, a COP of 4.0 or higher is considered very good. This means the chiller produces four units of cooling for every unit of energy consumed.
The Energy Efficiency Ratio (EER) measures the cooling output divided by the electrical power input. A higher EER indicates better efficiency. For modern chillers, an EER of 10 or above is considered good.
In practice, the efficiency of chillers can vary based on type, size, and operating conditions. Energy-efficient models meeting or exceeding industry standards, such as those set by ASHRAE or the U.S. Department of Energy, are typically regarded as high-efficiency options.