How does a hydronic heating system differ from a steam heating system?

A hydronic heating system utilizes water as the medium for heat transfer, which is fundamentally different from a steam heating system that uses steam. In a hydronic system, water is heated in a boiler and then circulated through pipes to radiators or other heat exchangers, where it releases heat to warm the surrounding space. This method tends to be more energy-efficient because water can retain heat longer and requires less energy to maintain at the necessary temperature.

On the other hand, a steam heating system generates steam, which is then distributed through pipes to radiators. These radiators condense the steam back into water, which must then return to the boiler for reheating. This cycle can result in more energy loss due to the phase change from water to steam and back to water. Therefore, option B accurately differentiates the two systems by highlighting that hydronic systems specifically use water, while steam systems operate with steam, setting the foundation for their operational efficiencies and applications.