Heat Pump Water Heaters: Performance at Varying Ambient Temperature

I recently received two graphs from AO Smith that show the difference in performance for their residential heat pump water heater, the Voltex.  A lot of manufacturers print performance at one condition.  The charts below shows the difference across the entire range. This data reiterates the importance of climate.

Heat Pump Ambient Temp Scale

Heat Pump Ambient Temp Scale1

Images Courtesy of AO Smith