How Do Hot Water Heaters Work?

Our Plumbing Company Explains

While cold water is great, hot water is simply better for some things (like washing dishes, showering, or washing clothes), and you probably have a water heater to do these things. But do you know how it works? Today’s water heaters come in styles like direct, indirect, and tankless, but what’s the difference between them all? And how do they work?

Essentially, hot water heaters work by using a heating mechanism to heat your water, and then pumping the water through your pipes. The heating mechanism is located either in the tank or in a separate boiler and there are different ways to receive your hot water. Here are the two most popular styles:


Direct water heaters are probably what you think of when you think of a water heater. These water heaters can be powered by electricity or gas and look like large metal cylinders. When cold water enters one of the two tubes at the top of the tank, it flows down to the bottom and is heated by either an electric mechanism or by a gas burner (depending on your power source).

Once the water is hot, it will rise to the top of the tank and when you turn on your faucet or start your appliance, it will flow out of the second tube and into your pipes. Both electric and gas direct water heaters can heat 30-80 gallons of water and keep it on reserve for when you need it.


Indirect water heaters can be powered by gas, electric, oil, or propane, and operate like direct water heaters. However, instead of having a heating mechanism inside the tank, it uses the heat from your furnace or boiler. Your furnace or boiler will have a pipe attached to the water heater. This pipe circulates hot water from your boiler to a heat exchanger within the water heater. This exchanger then heats the water in the tank and gives you anywhere from 30-100 gallons of water to use when you need it.

Which water heater you invest in depends on many factors, such as the size of your home, the size of your family, your main power source, energy efficiency, and more. Our West Chester water heater experts can help you choose the right one. Give us a call today.

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