When it comes to the difference between energy and power, our industry tends to get sloppy with its terminology. 

A tradeoff has always existed between the water temperature at which hydronic heat emitters are sized and their cost. The higher the supply water temperature assumed by the designer, the smaller the required heat emitters and the lower their installed cost. 

While I agree that heat pumps do move heat from one location to another, I strongly disagree with the premise that air-source and geothermal heat pumps are not renewable-energy heat sources.