What is an Indirect Water Heater?

What is an Indirect Water Heater?

An Intro to Indirect Water Heaters

If you heat your home with a boiler, you have the opportunity to get the most efficient hot water for showering, cleaning, and other uses with an indirect-fired water heater tank.


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What is an Indirect Water Heater?

Indirect Fired Water HeaterAlthough it's called a water heater, an indirect hot water tank doesn't heat the water itself. Instead, it circulates hot water from the boiler to a coil inside the tank. Heat from the water in the coil is then transferred to the water in the tank, which then flows to your fixtures. A separate thermostat communicates with the boiler when there's a need for domestic hot water.


Seasonal Energy Savings

In some parts of the country, the boiler is turned on in October and turned off in April. Having an indirect-fired water heater means that for about six months a year, your domestic hot water is provided by the already-operating boiler. In other words, the boiler takes care of the home heating and domestic water at the same time.

During the summer, when you do not need your boiler to heat your house, it will still turn on to heat the indirect hot water heater. This may seem to be the downside of this combination... but is it really?

For example, consider a high efficiency/modulating boiler with a capacity of 100,000 BTU. In the summertime, it will turn on at only 25,000 BTU, which still translates into a highly efficient system.

Most units also consist of a stainless steel tank that is very well insulated by a thermal plastic jacket on the outside, which means the water stays warm longer, no matter what the season.


What Size Should my Indirect Water Heater Be?

If you are replacing a conventional 40 or 50-gallon water heater and it was sufficient for your needs, simply match it up with a similar capacity indirect water heater.

For new construction and remodeling where additional bathrooms are added, or if you're installing appliances that require additional GPM (gallons per minute), such as Jacuzzi tubs or big size shower heads, it is always best to contact us and get advice from an expert.


Indirect-fired Water Heaters vs Conventional Water Heaters

Indirect Fired Water HeaterLet's compare an indirect hot water heater to a separate gas-fired water heater and boiler combination.

Conventional heaters are only about 50% efficient. In other words, for every $100 spent on gas for the water heater, $50 goes out through the chimney. An indirect-fired water heater, on the other hand, does not have a vent, which means that it is 99.9% efficient.

During the winter, both the boiler and water heater operate using two separate gas lines in a conventional water heater. Since an indirect hot water tank uses its connected boiler's energy, it does not require its own gas line.

Lastly, an indirect-fired water heater has no mechanical parts that can go wrong, and since it is composed of stainless steel, it is durable and will last for decades.


Indirect-fired Water Heaters vs Tankless Water Heaters

Indirect Fired Water HeaterA tankless water heater is a great appliance. It is far more efficient than a conventional water heater.

If a forced air furnace is used to heat the home instead of a hot water boiler, then a tankless water heater is the way to go. However; if a hot water boiler is present, adding the tankless water heater to take care of the domestic hot water is not the best solution.

Similar to a conventional water heater, a tankless water heater requires a separate gas line and even its own electricity source. In the winter time, the boiler and tankless water heater will operate using two separate gas lines and electricity sources, making the system not as efficient as expected.

 An indirect-fired water heater does not require electricity or gas and, therefore, does not need a vent. In fact, it's nothing more than a storage tank with a coil inside and inlet and outlet taps (connection points).

Depending on your home's specific hot water needs, it may turn out that two or more tankless water heaters are required. That is why an indirect water heater is the number one solution for the domestic hot water when a boiler is present.

Buying an Indirect Hot Water Tank

 At eComfort.com, we have many different brands of indirect fired water heaters. They all serve as excellent sources of domestic hot water and will work with any kind of boiler.

There are some small differences between them and prices will vary depending on the manufacturer. If you have any other questions about indirect water heaters, feel free to call us or email us, and we will be happy to answer all of your questions.


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Ken, the eComfort Product Expert
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