How Long Does a Tankless Water Heater Last? #LifespanGuide

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Endless hot water and up to 30% reduced monthly energy cost are the two biggest advantages tankless water heaters have over storage tank units.

At the same time, tankless water heaters have higher initial cost (oftentimes up to $1,000 USD and more). This is because the systems themselves are more expensive, and so is their installation.

In other words: It takes years for the investment to pay back. Thus, it is all the more important for a tankless water heater to last a long time.

But how long does a tankless water heater last actually?


Key Takeaways

  • Provided that operation and maintenance guidelines are followed, tankless water heaters can last between 15 to 20+ years.
  • Tip: Deliming your tankless water heater annually can further lengthen its lifespan.

Lifespan: How Long Do Tankless Water Heaters Last?

Electric or gas, the life expectancy of a tankless water heater is between 15 and 20+ years, provided that operation and maintenance guidelines are being followed. Many parts are also easily replaceable if need be.

Another important factor is water quality which in this case is mostly determined by hardness – think scale clinging to heating elements – and sediment content.

Pro Tip: Delime Your Tankless Water Heater about Once a Year.

Deliming your tankless water heater annually helps to ensure that there is no scale buildup around the heating elements which would not only raise your energy bills, but may also cause irreparable damage shortening the system’s lifespan.

Do Tankless Hot Water Heaters Last Longer than Tank-Based Heaters?

Traditional tank-based heaters have a 12-year lifespan, give or take. If you do the math, a tankless water heater lasts almost twice as long on average.

Why Do Tankless Water Heaters Have a Longer Life Expectancy?

The major problem with tank water heaters is corrosion due to moisture which they are exposed to 24/7. Some parts such as the heating elements can be replaced, but once the tank itself has failed, it’s over and you have to buy a whole new system.

And again, mineral content and overall water quality do their part as they can influence corrosion speed.

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If you have any questions about how long tankless water heaters last please don’t hesitate to leave a comment below!

About the Author Gene Fitzgerald

Gene Fitzgerald has been with BOS since the very beginning. She is head of content creation and has fully immersed herself into the home water treatment industry only to become an expert herself. Outside of BOS, Gene loves reading books on philosophy & social issues, making music, and hiking.
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Leave a Comment:

Carolynn Dillon says December 22, 2020

In your story on tankless water heaters, you mentioned Deliming the heating elements once a year. I couldn’t find instructions on how one would delime their unit. Please send instructions or website where I can find step by step instructions on Deliming my tankless water heater.
Thank you for your time.
Carolynn Dillon

    Gene says January 6, 2021

    There is plenty of information to be found online.

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