EER to COP Conversion
Worked example: COP 3.0 → EER 10.236 — press Try an example to run it live, then adjust anything.
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kW per ton →
UniversityFluid Mechanics, HVAC & Refrigeration
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EER to COP Conversion explained
The two numbers describe identical hardware; only the bookkeeping differs. COP is watts out per watt in — clean, dimensionless, and what the rest of the world quotes. EER divides BTU/hr out by watts in, which leaves the conversion factor 3,600/1,055.06 = 3.412 stranded inside the ratio. Multiply COP by 3.412 to get EER, divide to go back.
Useful landmarks: a minimum-efficiency US split system at EER 11 is COP 3.22; a good variable-speed machine at EER 14 is COP 4.10; a water-cooled chiller at 0.5 kW/ton corresponds to EER 24 and COP 7.0. The trap is arithmetic drift — 3.412 is often rounded to 3.41 or even 3.4, which shifts a COP-to-EER conversion by up to a third of a point, enough to move a piece of equipment across a rebate threshold. Worked example: COP 3.0 × 3.412 = EER 10.24; going the other way, a SEER-13 nameplate implies roughly COP 3.81 at its rating point.
EER to COP Conversion formula
- = Energy efficiency ratio (BTU/(h·W))
- = Coefficient of performance
Missing one of these? Work it out first, then come back
- Energy efficiency ratio — Energy Efficiency Ratio (EER), Energy Ratio Between Two Magnitudes
- Coefficient of performance — Coefficient of Performance (COP), Refrigeration COP from Enthalpies