COP And EER Calculator

Work out cop and eer instantly with clear inputs, formula shown and shareable results.

About COP And EER Calculator

EER is cooling output in BTU per hour divided by electrical input in watts, measured at a single rating condition. COP is the same ratio in consistent units, so dividing EER by 3.412 converts between them. Chiller plant engineers prefer kW per ton, which is simply 12 divided by EER.

Formula

Efficiency ratios

EER = BTU/h / W; COP = EER / 3.412; kW/ton = 12 / EER

Worked example

With the default values below, COP And EER Calculator returns Energy efficiency ratio of 11.25. Change any input above and every figure here is recalculated in your browser.

Inputs used

Cooling capacityminimum 1 BTU/h: 36,000 BTU/h
Electrical power inputminimum 1 W: 3,200 W

Results

Energy efficiency ratio: 11.25 BTU/h·W
Coefficient of performance: 3.297
Power per ton: 1.067 kW/ton
Capacity in tons: 3.00 tons

Step by step

1Values used
2Efficiency ratios
3Energy efficiency ratio= 11.25 BTU/h·W
4Coefficient of performance= 3.297
5Power per ton= 1.067 kW/ton
6Capacity in tons= 3.00 tons

Assumptions and limits

The result is derived only from the 2 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 3 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

How is the COP And EER figure worked out?

EER = BTU/h / W; COP = EER / 3.412; kW/ton = 12 / EER. EER is cooling output in BTU per hour divided by electrical input in watts, measured at a single rating condition.

How does SEER differ from EER?

EER is a single-point rating at 95 °F outdoor air. SEER averages performance across a simulated cooling season, so it is usually a higher number for the same machine.

What values do I need to enter?

This calculator takes 2 inputs: Cooling capacity, Electrical power input. The pre-filled defaults are a realistic worked example — replace them with your own site or project figures.