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.