Which of the following is an example of a radiant heating system?

A boiler system is considered a radiant heating system because it relies on the transfer of heat through hot water that circulates via pipes to radiators or underfloor heating elements. This method of heating provides warmth directly to the surfaces in a space, which then radiates that heat to the occupants and the environment, offering a comfortable and efficient way to heat a room.

In contrast, a heat pump works by transferring heat from one location to another and typically operates using air or ground-source methods, which are not classified as radiant heating systems. Similarly, a forced air furnace heats air and distributes it through ducts, relying on moving hot air rather than direct surface heating. A ceiling fan, on the other hand, is a ventilation device that circulates air but does not provide heating by itself, making it unrelated to radiant heating systems. Thus, the only choice that fits the criteria for a radiant heating system is the boiler system.