What distinguishes hydronic heating systems from forced-air systems?

Hydronic heating systems are characterized by their use of hot water to circulate heat throughout a space. The water is heated in a boiler and then distributed through a network of pipes to radiators or floor heating systems, which release the warmth into the room. This method of heating is generally more efficient and provides a more even temperature when compared to forced-air systems, which rely on blowing heated air through ducts.

The use of water as a heat transfer medium is crucial, as water has a high specific heat capacity, meaning it can hold and transfer more heat compared to air. This difference in heat transfer methods is a fundamental distinction between hydronic heating and forced-air systems, which do not use water at all.