The orange graph and table above show that even at -7ºC (19ºF) ambient air temperature and a very hot 40ºC (104ºF) water temperature the ARCTIC 025ZA/B heat pump can still deliver 6.5 kW of heat into the water, while only consuming 2.19 kW itself, for a COP of 2.97. Other units produce similar COP results, +/- 5%. These are the worst conditions and at higher ambient temperatures or lower water temperatures, efficiencies just get better. During a fresh fill, for example, the water temperature is much lower (such as 50ºF (10ºC)) and with high ambient air temperatures you can expect significant improvement on the COP (over 6), during the initial heating of the cold water. However, in the longer term, most of the heat needed just to maintain the water at its normal temperature (28ºC for a pool and 39ºC for a hot tub) and the blue and orange graphs apply. The heat pump will then deliver an equal amount of energy to the water, as the water gives off due to heat losses.