So I would say it is the middle of winter. Maybe not by the calendar, but the thermometer says so. From my observations, the electricity usage for the hot water heat pump have increased from 3.33kW hours to about 4kW hours per day on average.  This increase can be attributed to three factors.

  1. The incoming water temperature has decreased because of colder ground temperatures.
  2. The heat pumps ambient air temperature has decreased.
  3. The shower “anti-scald valve” has caused me to increase the tank temperature.

Factors explained.

  1. This is easy. Colder air temperatures cause the ground temperatures to go down also.
  2. I would say the air temperature in the summer for the heat pump was about 80 degrees. Now it is around 60 degrees.  This makes the heat pump work heard to get the tank back to the set point.
  3. The shower fixtures in my house have a anti-scald valve. This is for safety. This means that cold water is always mixed with incoming hot water and that comes out of the shower head. I use to have the tank set at 120 degrees. Now I have to have it set at 125 degrees to get the same hotness of water at the head. I was also informed today that “my shower was not hot enough”, so I may have to increase the tank temp. again.

If I had my old gas tank, I would only have to deal with 1 and 3. Personally, I think it is 1 and 3 that are causing the biggest increase in energy usage. This means I am still money ahead in using my hot water heat pump.

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