Physics
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Coefficient of Performance Calculator.
Calculate heating or cooling coefficient of performance from useful heat and input work.
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Results update as you type.
Results update automatically as you type.
Use Cases
Evaluate heating system efficiency
Use this calculator to compare the efficiency of different heating systems by entering their useful heat output and work input. This helps in selecting a more efficient system.
Example: Compare a heat pump with useful heat 8000 J and work 2000 J (COP=4) vs. an electric heater with useful heat 3000 J and work 3000 J (COP=1).
Assess cooling performance
For air conditioners or refrigerators, calculate the COP to see how effectively they remove heat relative to the work consumed. This aids in energy cost estimation.
Example: An air conditioner removes 6000 J of heat with 1500 J of work, giving a COP of 4.
Frequently Asked Questions
- What is the coefficient of performance (COP)?
- The coefficient of performance (COP) is a measure of efficiency for heating or cooling systems. It is the ratio of useful heat output (in joules) to the input work (in joules). A higher COP means more efficient operation.
- How do I calculate COP using this calculator?
- Enter the useful heat in joules and the input work in joules. The calculator divides useful heat by input work to give the COP. For example, if useful heat is 5000 J and input work is 1000 J, COP is 5.
- What does a COP greater than 1 mean?
- A COP greater than 1 indicates that the system delivers more useful heat than the work input. This is typical for heat pumps and refrigerators, as they transfer heat from a source to a sink, often achieving COP values above 1.
Tips & Common Mistakes
Tips
- Ensure both useful heat and input work are in joules. If your values are in other units, convert them first to get an accurate COP.
- For heating systems, a higher COP indicates better efficiency, but consider the temperature conditions as COP can vary with operating conditions.
- Use this calculator for quick estimates; for detailed analysis, consult system specifications or a professional.
- Remember that COP is dimensionless, so the result is a ratio without units.
Common Mistakes to Avoid
- Using different units for useful heat and input work without conversion, leading to incorrect COP values.
- Confusing COP with efficiency percentage; COP is a ratio, not a percentage, though it can be expressed as a percentage by multiplying by 100.
- Entering values in kilojoules or other units but assuming they are joules, which skews the result.
Last updated: August 13, 2026