Focus on Energy: Combination Space and Water Heaters

Boilers with "sidearm" water heaters have been around for generations in the Northeast. But in the rest of the country where forced-air heating is king, the concept of integrated space and water heating may seem foreign. While they may not be for everybody, several types of systems that use a single appliance for both space and water heating are worth considering. Introducing the "Hydronic Furnace" The term "hydronic furnace" usually causes my engineering friends to cringe. But it does accurately describe a type of heating appliance that uses a hot water coil to heat air. As a central heating system, it resembles an electric furnace in which the electrically heated coil has been replaced by a hydronically heated coil—thus the term