COP to EER Converter
Instantly convert Coefficient of Performance (COP) to Energy Efficiency Ratio (EER) for air conditioners, heat pumps, and chillers. Accurate for comparing HVAC efficiency ratings across regions.
Calculate Your Efficiency Rating
Enter your COP value below to get an instant, accurate conversion to EER, or switch direction to convert EER back to COP.
Efficiency Converter
Enter your COP value to see the equivalent EER
Found on heat pump and chiller datasheets as a dimensionless ratio
Switch direction to convert EER back to COP
Converted Efficiency
Calculated using the standard COP ⇄ EER factor
COP to EER Conversion Chart
Common COP values converted to EER. Use this to quickly cross-check air conditioner, heat pump, and chiller efficiency specifications.
| COP | EER | SEER (approx.) | Efficiency Level |
|---|---|---|---|
| 2.5 | 8.53 | ~9.8 | Low efficiency / older unit |
| 3.0 | 10.24 | ~11.8 | Standard efficiency |
| 3.5 | 11.94 | ~13.7 | Mid-range residential AC |
| 4.0 | 13.65 | ~15.7 | High efficiency unit |
| 5.0 | 17.06 | ~19.6 | Premium heat pump / VRF system |
COP to EER FAQ
Everything you need to know about converting between COP and EER efficiency ratings.
To convert Coefficient of Performance (COP) to Energy Efficiency Ratio (EER), multiply the COP value by 3.412. This factor converts the dimensionless COP ratio into EER, which is expressed in BTU per watt-hour.
A COP of 3.5 is equal to an EER of approximately 11.94, calculated as 3.5 multiplied by 3.412. This is a typical efficiency level for a mid-range residential air conditioning unit.
COP is a dimensionless ratio of useful heating or cooling output to energy input, commonly used in Europe and for heat pumps. EER expresses cooling output in BTU per hour divided by power input in watts, and is the standard rating used in the United States for air conditioners.
To convert EER back to COP, divide the EER value by 3.412. For example, an EER of 13 divided by 3.412 equals a COP of approximately 3.81.