Wanderport Corp (WDRP)

[water boy]

Heat pump is a very prudent concept. It uses free ambient heat and merely move it from one place to the other. That is how it could have a funny E.F of 2.4, because all it does is to mainly move existing ambient heat to its heat engine. It does not have to produce heat.

Anyhow, this beautiful concept has its limitation. First, it probably has a difficult time working efficiently in a colder region. Second, its size cannot be as compact as those tankless units. In other world, you cannot anticipate a tankless heat pump water heater, since it requires a water tank to store the heat. This is merely IMHO. I could be wrong since it has been a long time learning this subject.