Refrigerator COP Calculator

About this calculator

This calculator finds the theoretical maximum coefficient of performance of a refrigerator, the Carnot COP = T_c/(T_h−T_c), where T_c and T_h are the cold and hot reservoir temperatures in kelvin. COP measures how much heat is removed from the cold space per unit of work input — a value that can exceed 1, unlike a simple efficiency ratio — and the Carnot limit represents the absolute best any refrigeration cycle could achieve between those two temperatures, a direct consequence of the second law of thermodynamics.

HVAC and refrigeration engineers use this Carnot benchmark to see how far a real refrigerator, heat pump, or air conditioner's actual COP falls short of the theoretical ceiling, which highlights where a design has room for efficiency improvement. Appliance designers use it during early-stage design to set realistic performance targets, and thermodynamics students use this calculator to connect the abstract Carnot cycle to a device they use every day.