• Energy & Power

Tankless Coil and Indirect Water Heaters



A home’s space-heating system can also be used to heat water. Two types of water heaters that use this system are tankless coil and indirect. No separate is needed in the tankless coil because water is heated directly inside the boiler in a hydronic (i.e., ) heating system. The water flows through a heat exchanger in the boiler whenever a faucet is turned on. During colder months, the tankless coil works well because the heating system is used regularly. However, the system is less efficient during warmer months and in warmer climates when the boiler is used less frequently.

A tankless coil water heater uses a heat exchanger in the boiler to heat water.

A separate storage tank is required with an indirect water heater. Like the tankless coil, the indirect water heater circulates water through a heat exchanger in the boiler. But this heated water then flows to an insulated storage tank. Because the boiler does not need to operate frequently, this system is more efficient than the tankless coil. In fact, when an indirect water heater is used with a highly efficient boiler, the combination may provide one of the least expensive methods of water heating.

A combination of an indirect water heater and a highly efficient boiler can provide a very inexpensive method of water heating.