Hydronic Heating Systems
Hot-water heating systems use water as the medium for conveying and transmitting the heat to the various rooms and spaces within a structure. The motive force for the water in these systems is based either on the gravity flow principle or forced circulation. The latter type (referred to as hydronic, or forced-hot-water heating) is the one currently used in residential and commercial heating system. In a typical hot-water heating system, the water is heated in a boiler or water heater and circulated through pipes to baseboard convectors or radiators located in various rooms. The energy source used to heat the water may be oil, natural gas, propane, electricity, or a solid fuel, depending on the heating unit.
The hot water is circulated through pipes to baseboard convectors or radiators located along the walls of the rooms, or through radiant panels installed in the floors or ceilings. A centrally located thermostat controls room temperatures in smaller houses or buildings. When the thermostat calls for heat, the boiler or water heater heats the water and sends it to the room convectors or radiant heating panels where it is released and distributed through the rooms by natural convection. In larger houses or buildings, the heating system is zoned with individual thermostats controlling the temperatures in each zone.