How does it work?

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2016 Corvette Stingray 2LT
1969 280SE
2023 Ram 1500
2007 Tiara 3200

Apparently, it's a simple heat pump. It takes heat from the surrounding area and transfers it to the water. The efficiency of taking heat from 70° ambient air and attempting to heat water to 130° is highly questionable. Think about the energy needed to take heat from a 70° room and dispose of it in a 90° room (outdoors). A simple 20° differential reduces the efficiency of the typical a/c unit to about 3:1. He's looking at a 60° differential............the efficiency isn't going to be better than 1:1.

Some folks at GE think they can do better than that.

Heat pump water heaters aren't in general a new idea, are they? They just haven't achieved wide popularity in the past.

I'll believe 2:1 with a 60° differential when I see it with my own two eyes.

http://www.aceee.org/consumerguide/waterheating.htm

No statement of differential in that article..........which is critical to the efficiency...........they could easily assume a 40° differential for the sake of a much better efficiency figure.

Applied Energy Recovery Systems shows some data sheets that include graphs of their (claimed) coefficient of performance as a function of final tank temperature, with curves for different ambient temperatures. Here's the data sheet for one of their residential units.

I read that AERS was acquired by A. O. Smith not that long ago.

Really?

http://www.energy.wsu.edu/documents/building/res/ht_pmp_water_htrs.pdf