What aspect of hydronic heating systems is described in terms of heating methods?

Hydronic heating systems primarily utilize hot water as a medium for transferring heat throughout a building. This method relies on the circulation of heated water through pipes or tubing, which then radiates warmth into the spaces they serve. The effectiveness and efficiency of this heating approach is one of its standout features, as water can hold a significant amount of heat and distribute it evenly across various areas of a home or building.

In contrast, the other options refer to different heating methods or mechanisms. Electric heating uses electrical energy to generate heat, radiant heating focuses on delivering warmth directly from a heat source to objects or people in a space, and conduction specifically describes the process of heat transfer through direct contact between materials. These concepts, while related to heating, do not capture the specific functionality of hydronic systems, which distinctly rely on the movement of hot water to achieve their heating effect.