What type of HVAC system uses water to distribute heat?

The correct answer is the hydronic heating system, which is designed specifically to use water as a medium for distributing heat throughout a building. In a hydronic system, water is heated in a boiler and then circulated through a network of pipes to radiators or underfloor heating elements. This method allows for a consistent and efficient transfer of heat, providing comfortable warmth in the spaces being heated.

Hydronic systems have several advantages, including greater energy efficiency and the ability to maintain more stable temperatures compared to some other heating methods. The use of water as a heat transfer medium can also lead to lower operating costs since water holds and distributes heat effectively.

In contrast, a forced air system circulates heated or cooled air through ductwork, making it reliant on air rather than water. An electric heating system typically uses electric resistance to heat air or surfaces directly and does not involve the circulation of water. A refrigerant cooling system focuses on removing heat from the air using refrigerants, which is unrelated to heating through water. Understanding these distinctions highlights why hydronic heating is uniquely suited for the distribution of heat using water.