Manufacturers of products certified by the Air-conditioning and Refrigeration Institute (ARI) Standard 325 for ground water-source heat pump equipment publish a capacity rating for each model catalogued at the standard entering water rating conditions of both 70 and 50°F for cooling and heating. The cooling EER, heating COP and fluid flow for both is also published.

In calculating the cooling Standard Energy Efficiency Rating (EER) and the heating Coefficient of Performance (COP), a penalty for the water pump effect is added to the measured power input.

You should not confuse the ARI Standard Energy Efficiency Rating with the expression SEER. The latter stands for Seasonal Energy Efficiency Ratio. SEER is a measure of seasonal cooling efficiency under a range of weather conditions, assumed to be typical for a location, and of performance losses due to cycling under part load conditions.