Coefficient of Performance (COP) Calculator

COP equals the heat transferred divided by the work input. In cooling mode use the heat removed from the cold space (Qc); in heating mode use the heat delivered to the warm space (Qh). Both divide by the same work W.

The division is identical in both modes; the mode only changes which heat you enter and how the result is labeled. Cooling uses Qc and heating uses Qh, so switch the mode to match the machine you are analysing.

Air conditioners and refrigerators typically show a cooling COP of about 2 to 4, while air-source heat pumps often reach a heating COP of 3 to 5. Ground-source systems can go higher. In every case a bigger number means more heat moved per joule of work.

COP is not a thermal efficiency capped at 100 percent. A heat pump moves heat that already exists rather than generating it, so it can deliver several times more heat energy than the electrical work it draws, giving values well above 1.

For the same machine the heating COP is the cooling COP plus 1, because the heat delivered equals the heat removed plus the work input (Qh = Qc + W). A unit with a cooling COP of 3 therefore has a heating COP of about 4.

Enter both heat and work in joules; the tool divides them so the COP is dimensionless. If you have power in watts measured over the same time, the ratio is the same, since the shared time cancels out. Just keep both fields in matching units.

Both fields must be filled with finite numbers, and both the heat and the work must be greater than zero. Zero or negative work would mean dividing by zero or worse, so the tool asks for positive values before it computes.

COP is dimensionless and uses SI units. EER divides cooling output in BTU per hour by input in watts, so it is roughly 3.41 times the cooling COP. SEER is a seasonal average of EER across a range of conditions.

No. The calculation runs entirely in your browser with a single division, so the heat and work values you type never leave your device and nothing is stored or uploaded.