John Siegenthaler Investigates: Low Ambient Air-to-Water Heat Pumps Low Ambient Air-to-Water Heat Pumps: An emerging renewable heat source for North American hydronic systems. Electrically powered heat pumps, in many varieties, are destined to play an increasingly important role in heating and cooling buildings around the world. Heat pumps capture… Continue reading “John Siegenthaler Investigates: Low Ambient Air-to-Water Heat Pumps”