How Do Tankless Water Heaters Work?


Tankless water heaters have quickly become one of the most popular home upgrades for homeowners everywhere. Using cutting-edge technology, these units take away a number of the negatives and shortcomings of a traditional tank-style water heating system. How do they do it? With some clever engineering and some pretty simple concepts that make older, tank-style units seem downright impractical. Many people who install these systems are so happy with their decision that they wonder why they didn’t make the change sooner.

How do these appliances work? In this blog, we’ll explain what makes these systems tick and they’re so much better for you and your home than their predecessors could have ever hoped to be.

The Tankless Heating Process

Tank and tankless water heaters have a few things in common. Both rely on electricity for control and ignition. Both require a gas connection to serve as fuel that heats the water (and likewise, both come in electric-powered models that use electrical heating elements instead of gas burners). And likewise, both have a direct connection to your main water input and hot water lines that stretch throughout your home.

However, beyond that, the two systems could not be more different. A tank-style water heater filled up a giant tank with water and then used either a gas burner or electrical heating elements to bring the water in that tank up to temperature. The process was slow, inefficient, and could take upwards of an hour or more to complete if a larger tank was completely drained. All the while the water flowing through your hot water lines would be cold, making for a horribly uncomfortable shower or poorly washed load of laundry.

Tankless water heaters are a different story. As their name implies, tankless water heaters don’t actually have a tank, but instead focus on heating a very small quantity of water extremely quickly. This is accomplished through a heating coil located in the heating unit itself. Water flows into this heating coil, where high-power heating elements imbue it with an immense amount of heat in an extremely small amount of time. However, because the heating coil contains a much smaller volume of water, it takes significantly less energy and time to bring the water up to temperature. By the time the water flows through the coil (in a few short seconds), it has already reached your ideal temperature and is ready for use in your home.

In this way, water continuously flows through your tankless water heater, and your water heater continuously produces hot water. When you shut off your hot water tap, the flow from your water heater shuts off too, cutting off the fuel flow and idling your unit until it is needed again. This means that unlike a tankless water heater, you will never run out of hot water again. That’s something that every homeowner can smile about.

Tankless Water Heaters Save Energy

Tankless water heaters not only provide you with a limitless supply of hot water that your home can use, but they can also save you money in the process of doing it. How? Because tank-style water heaters actually waste a significant amount of energymaintaining the tank temperature. This is yet another flaw of the tank-style heater design—no matter how well you insulate your tank, it will slowly lose heat. The water inside the tank will slowly cool off, and thus your heater will have to turn on again periodically to reheat the water back to your temperature target. If nobody is home for the majority of the day, your heater may cycle several times without anybody using a single drop of water from the tank itself. That’s a ton of fuel wasted just keeping your tank at temperature while nobody is using it.

Tankless water heaters, on the other hand, don’t keep a tank of water at temperature. Instead, they simply turn the heating elements on when you need hot water somewhere in your home, meaning you never actually consume any energy unless you’re using hot water. This can save you hundreds over the course of an entire year, and can even help your tankless water heater pay for itself over the typical lifespan of a traditional tank heater (roughly 8 years or so).

Want to bring the power of tankless water heating to your home? Call Carter Quality Plumbing at (803) 998-2270 now to request an estimate for your tankless water heater installation.

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