Manufacturers of products certified by the ARI Standard 325 for groundwater-source heat pump equipment publish a capacity rating for each model, cataloged at the standard entering water rating conditions of both 70 and 50 degrees 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.
The ARI Standard EER should not be confused with the SEER, or 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.