Energy Efficiency Ratio (EER) is a metric used in Imperial units to measure the energy efficiency of cooling equipment , such as industrial chillers, air conditioners, and heat pumps. A higher EER means better cooling performance for the same amount of power consumed. How do you calculate EER?

To make calculations easier, we’ve created an EER calculator. Simply select the correct unit system and enter the value to determine your equipment’s EER. For those interested in manual calculations, we’ve also provided a detailed calculation method below the calculator. We hope this helps.

Energy Efficiency Ratio (EER) Calculator

Enter the values below to calculate EER and the corresponding COP.

Cooling Output:
BTU/hr

Power Input:
W

How to Calculate Energy Efficiency Ratio

EER is most commonly used in the imperial system. It is defined as the ratio of cooling capacity (BTU/h) to power input (W):

EER = Cooling capacity (BTU/h) ÷ Input power (W)

For example, if a chiller delivers 15,000 BTU/h of cooling and consumes 1500 W of power:
EER = 15,000 BTU/h ÷ 1,500 W = 10 (BTU/h·W).

EER is commonly used for cooling equipment, while COP is also used for heating equipment. So how do we convert COP and EER? Let’s review how to calculate COP:

In the metric system, cooling capacity is expressed in kilowatts (kW), and COP is the ratio of cooling output to electrical input, both measured in kW.COP is calculated using the metric system:

COP = Cooling capacity (kW) ÷ Input power (kW)

For example, an industrial chiller’s nameplate states a cooling capacity of 80 kW. In one hour, it consumes 20 kW of electricity. Its COP is:

COP = 80 kW ÷ 20 kW = 4.0

This means the unit delivers 4 kW of cooling per 1 kW of electricity consumed.To convert between EER and COP, you need to understand the unit conversion:

1 kW = 1000 W
1 kW = 3412 BTU/h
1 W = 3.412 BTU/h

Therefore:
Cooling capacity (BTU/h) = Cooling capacity (W) × 3.412

So we get:
COP = Cooling capacity (W) ÷ Input power (W)
EER = Cooling capacity (BTU/h) ÷ Input power (W) = Cooling capacity (W) × 3.412 ÷ Input power (W) = COP × 3.412

Thus:

EER = COP × 3.412
COP = EER ÷ 3.412

Examples:
If COP = 3, EER = 3 × 3.412 = 10.236
If EER = 12, COP = 12 ÷ 3.412 ≈ 3.52

Conclusion

We hope this guide helped clarify how EER is calculated.Still have questions? Our team is here to help. Looking for a high-efficiency industrial chiller? LNEYA offers custom chiller with a variety of performance options.

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