All Heat Pumps that are sold in New Zealand are required to have a star rating and must meet a Minimum Energy Performance Standard (MEPS). The MEPS (Minimum Energy Performance Standard) for New Zealand is a COP (Coefficient of Performance) (Heating) and EER (Energy Efficiency Rating) (Cooling) of 2.3. All appliances that reach this level are awarded 2 stars. For every .3 increase in either the COP or EER the appliance receives another star. All Heat Pumps have two star ratings, one for heating and one for cooling. The more stars the more energy efficient.