While it is clear from the Addendum of the RESNET/ANSI Standard 301-2014 that the temperature of the cold water entering the water heater is used in the determination of the Rated Home’s fixture hot water mix fraction (adjFmix), it is not explicitly stated that the hot water inlet temperature (HWinT) that is used to determine adjFmix should also be used to determine the standard energy consumption (stdECHW) for the hot water system. RESNET has issued a standard interpretation to make the use of HWinT explicitly clear in the calculation of standard hot water energy consumption values. The interpretation states: The value(s) for the water heater inlet temperature, WHinT, used to determine adjFmix for equation 4.2-11 shall be the value(s) for water heater inlet temperature used to calculate standard hot water energy consumption, stdECHW, for equation 4.2-16 The interpretation goes into effect on July 22, 2015
