Hydronics is a heating and cooling technology that relies on water to transfer heat energy into or out of a space. These systems are an alternate to traditional forced-air heating and cooling, and provide many advantages in certain types of applications. Unlike standard cooling or refrigeration systems, hydronics utilizes water, rather than refrigerant to transport heat energy.
The earliest hydronics system included steam heating systems, which used steam to heat a space or operate industrial equipment. Modern systems rely on hot water to heat a room through a standard radiator or baseboard heating system. Large industrial boilers also rely on hydronics principles to heat a building or power certain types of equipment. Hydronics is also used to supply heat to undefloor radiant heating systems.
A standard hydronic heating system relies on a central boiler to heat water. This hot water is then carried through the building through a network of pipes, which deliver hot water to radiators or heating units. These units radiate heat into the space until much of the heat energy in the water has been dissipated. The cooled water then travels back to the boiler for re-heating.
Similar technology allows builders to use hydronics in a cooling or refrigeration system. Water is cooled in a central chiller or heating tower. This cool water travels to radiators and cooling units in each room. The water absorbs excess heat energy from the space, leaving it cool and comfortable. The heated water then travels back to the chiller or cooling tower to release this heat energy.
Hydronic systems provide very even and consistent heating and cooling, with none of the drafts or hot/cold spots associated with forced-air systems. They also create a moist heat, rather than the dry heat of a traditional furnace and duct system. By eliminating the need for ductwork, hydronic systems also improve the energy efficiency of a structure. This is due to the fact that these systems deliver hot and cold water right where it is needed, with no energy lost through uninsulated or unsealed duct transitions.
In homes that utilize a standard duct-based heating and cooling system, hydronic systems require a substantial upfront investment. Homeowners may pay to install new piping, and also to purchase a boiler or chiller. Some homeowners may be unhappy with the time it takes for the average hydronics system to heat or cool a space. Unlike forced air systems, which deliver heated or cooled air immediately, hydronics systems take time to heat or cool the water prior to operation.