Service records for small capacity console ("perimeter") water-loop heat pumps and larger capacity vertical and horizontal ("CORE") water-loop heat pumps in commercial office buildings were examined in order to estimate the median service life of their compressors. The median service life of the heat pumps themselves is the same as the median service life of the building in which they are installed, since the heat pumps are virtually never replaced, although they may be removed for bench repair and then returned to service in the same building.

KEYWORDS: service life, water heat pumps, commercial, offices, calculating, compressors, buildings, performance, durability.