Nicolette Forbes

By: Nicolette Forbes on May 4th, 2022

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How Long Does a Tankless Water Heater Last?

Tankless Water Heaters

Are you in the market for a new tankless water heater but are unsure how long it will last? Or are you thinking about switching from a conventional water heater to a tankless unit and are curious which one has longevity?

Here at Monkey Wrench, we work with thousands of property and homeowners to properly install and replace tankless water heaters. Through that process, we have helped people just like you figure out how long their tankless will last and if it's the right option for them. Whether we install your tankless water heater or not, we want to make sure you are as informed as possible about tankless systems. 

In these next few sections, we are going to touch on 

  • what a tankless water heater is
  • what factors affect the lifespan of your tankless unit
  • how you can get the most out of your tankless water heater. 

By the end of this article you will know how to make your tankless water heater stand the test of time.


What is a tankless water heater? 

Before we jump into the longevity of a tankless water heater, let’s briefly touch on what a tankless water heater is.

A tankless water heater is a device that heats your water without the bulkiness of a tank. Unlike a conventional water heater that is storing the water inside the tank, a tankless water heater has nowhere to store water and heats the water  on demand as it moves through the heat exchanger, ultimately providing you an endless supply of hot water. A diagram of how a tankless water heater works inside


Some of the popular brands of tankless water heaters include Noritz, Navien, and Takagi. And if you’re looking for more information on what tankless water heaters are and how they compare to conventional water heaters we offer more information here.


How long does a tankless water heater last? 

The lifespan of a tankless water heater is not so cut and dry. Its longevity can vary depending on the type of heat exchanger installed in your unit. If you’re unfamiliar with heat exchangers and want to know more about them, we go more in-depth on the subject here.

On average, a tankless water heater can last up to 20 years with proper yearly maintenance. With a copper tankless heat exchanger, your tankless water heater has a warranty of 12-to-15 years. However, with proper water treatment and by doing maintenance once a year, typically the tankless water with a copper heat exchanger can last anywhere from 12 to 20 years.

With a stainless steel heat exchanger in your tankless water heater, its lifespan increases. A standard warranty for a tankless water heater with a stainless steel heat exchanger is 15-to-25 years. And once again, with the proper maintenance and water treatment, the tankless water heater can last about 25-to-30 years.

A Noritz tankless water heater

Learn more about what tankless maintenance is and what it entails, we have more information for you here!


Signs It’s Time For Maintenance On Your Tankless Water Heater

It is recommended that you get maintenance performed on your tankless water heater once a year but how do you know it’s time for a checkup on your unit? 

Well, there are a few ways to tell that it's time to get maintenance done on your tankless water heater whether it's an old or a new model.

    1. Error Code
    2.  Reset Unit

If you find that your tankless water heater is showing any error codes or that you are having to restart your water heater, then it may be time to get maintenance done on your tankless. BUT I don’t want to overwhelm you with even more information, so be sure to check out our article here that goes further in depth about what are the top issues faced with a tankless water heater and what to do when it happens. 


Prolonging the Lifespan of Your Tankless Water Heater

We now know what to look for when it comes time to get maintenance done on your tankless water heater but now you must be wondering, “Well, how do I avoid all that and make my tankless unit last its full life?”

Prolonging the lifespan of your tankless water heater relies on several different factors.

      1. Maintenance

OnOne fofe of the top ways to get the most out of your tankless water heater is getting yearly maintenance done on your unit. Lack of maintenance will cause early breakdowns regardless if you have water treatment or not. As mentioned before, maintenance is super important! 

While sometimes it may seem like a quick fix, having maintenance done isn’t just flushing out the water heater. Sometimes there could be other issues like using an automatic compressor to fully clean out the debris or lint that can get into the internal parts such as the fan. Maintenance for a tankless water heater can last anywhere from 60-to-90 minutes.


  1. Hard Water

Another way to prolong the life of your tankless water heater is to avoid having hard water. If you are in an area that has hard water, like much of Los Angeles, it is highly recommended that you get water treatment to prevent early breakdowns. Not having a water treatment with hard water can slowly start to cause a leak in the heat exchanger or early failure of parts inside the unit.

So while keeping up with maintenance is important, having water treatment serves as that extra protection for your tankless water heater. Additionally, we have links here that will guide you through what is a water treatment, hard water and the different components of a tankless water heater. As well as any D-I-Y maintenance tips from our trusted technicians.

Steps to Flushing Tankless Water Heater

Hard Water: What it does and what does it do to your home?


Long Live the Tankless Water Heater

So to recap, we touched on what a tankless water heater is, how long it lasts, what signs to look for when it’s time to get maintenance done on your unit, and how to prolong its lifespan. 

With proper maintenance and water treatment, a tankless water heater can last anywhere from 12 to 30 years. 

There are also ‘error codes’ that can appear on your tankless unit or the unit’s remote that will tell you when it’s time to get your water heater checked out.

In addition to the error codes, if you find yourself having to reset your tankless water heater, it’s also highly recommended that you still get your tankless water heater checked for maintenance as it could prevent bigger issues in the future.

We here at Monkey Wrench Plumbing have been dedicated to giving you the most accurate information to make the best decision for yourself and your home since 2007. If you’re in the market for a tankless water heater and still have more questions, click on these links below for more information on the benefits of having a tankless water heater, the types of maintenance it requires, which water heater size is the best for you and how it compares to a conventional water heater. 

The Six Benefits of Having a Tankless Water Heater

Two Types of Tankless Water Heater Maintenance

Steps to Determine Which Tankless Water Heater Size is Best For You

Or if you have any other questions you can always reach us here at 310-853-8690 and we’d be happy to assist you.