The energy stored by the water tank allows the furnace to turn off and on less often, which saves you money!
Indirect water heaters offer a more efficient choice than typical storage tank heating systems for most homes, even though they still require a storage tank. An indirect water heater uses the main furnace or boiler to heat a fluid that's circulated through a heat exchanger in the storage tank. The energy stored by the water tank allows the furnace to turn off and on less often, which saves energy. Therefore, an indirect water heater is used with a high-efficiency boiler and well-insulated tank can be the least expensive means of providing hot water.
Indirect systems can be fired by gas, oil, propane, electric, solar energy, or a combination of any of these. Tankless systems are typically electric or gas-fired. Also, these integrated or combination water heating systems not only can work with forced air systems, but also with hydronic or radiant floor heating systems.
To review additional water heating options, click any of the following technologies: Tankless (On-Demand), Solar Water Heaters, High Efficiency Gas Storage Water Heaters and Geothermal Water Heaters