[KMag]

As others have pointed out, the coefficient of performance is over 1.0. However, as I remember from my mechanical engineering classes, a single-stage piston compressor based refrigeration system found in most window-mount AC units, refrigerators, etc. typically operates at about half of the Carnot efficiency. Central AC units with scroll compressors do a bit better, and of course industrial chillers with multi-stage centrifugal compressors do quite a bit better.