How Many Years Does a Tankless Water Heater Last?

how many years does a tankless water heater last

If you are here, that means you are opting between the tankless water heater and the one with storage. Let’s be clear, there are several advantages of a tankless water heater, and lifespan is definitely among them.

You’ve probably realized that the tankless water heater is quite worthier than the regular one, but you are wondering for how long will such investment last.

How Long Does a Tankless Water Heater Last?

Most of them have two times or even three times longer lifetime than the regular water heater. That’s around 20 years. But it all depends on the quality of a tankless water heater- you might even expect 30 years of service.

What’s more important, these heaters have easily replaceable parts. You will simply change everything that needs to be fixed and prolong its life even more. Compared to a storage water heaters that last around 10-13 years, these are quite a worthy investment, if you plan on staying in your home for a while.

Even if you are not spending a lot of time in your home, it’s nice to pay it forward towards the overall cost savings of home ownership.

Unlike storage water heaters that keep the water within their storage, tankless water heaters have no storage, and hence, they are less prone to rust and corrosion.

Once storage water heaters start to rust, you can say farewell. All of its parts are much harder to replace, and the costs of hiring a plumber are extremely high.

However, on the other side, we have tankless water heaters that are not prone to rust at all. No storage, no problem. Anyway, you might face occasional problems and even so, you will easily deal with such issues as replacing of parts is like a walk in the park.

In most of the cases, you can solve the problem yourself. Just watch some youtube tutorials and voila.

So, let’s sum it: tankless water heaters have no storage, hence are less prone to rust and corrosion, and changing the parts that are out of order is quite easier than with storage water heaters. When we do the math, that’s around 20 years longer lifespan of a tankless water heater compared to a storage water heater.

How to Check Your Tankless Water Heater Lifetime

So, you just moved to another house, and owners told you that they are unaware of the tankless water heater’s age. How can you know whether it is old or a new one, and how much years of service is there left.

Well, no matter if you are in a new house, or just don’t track down the documentation of the things you buy, there is a simple solution to find out how old your tankless water heater is. The key is in its serial number.

Located on the upper portion of a water heater, there is a serial number with a bunch of strange markings. The one that you are looking for is that with a letter followed by a series of numerals. For example, you can find marking B12. What does that mean?

Well, it simply means that your tankless water heater was manufactured February 2012. In the tankless water heater’s world, months are marked as letters A,B,C… starting from January. So, the first month (January) is A, the 2nd (February) is B, and so on.

This rule applies to almost any tankless water heater manufacturer- they will all put such symbols to mark the year of production.

However, if you see some strange letter like Ž10, you would probably want to check on the manufacturer’s website for the meaning of such letter.

Signs of an Aging Appliance and when is the Time to go Tankless

So, how can you know if your water heater stepped into the second half of its life? Pretty simple. There are some signs of your heater aging, and they are pretty clear sometimes. Let’s check them out:

  • You can hear a rumbling or banging noise- This can often occur with those water heaters that are running short on life. There is a general recommendation that almost every manufacturer gives about flushing of a tank-style once a year, no one really does that. As a consequence, there is calcium buildup all over the bottom of your tank, and sooner than you know, there is a thick crust that makes your heater bang and creak while working.
  • Strange colored water- If you notice that there is some red or yellowish hot water running down your faucet, that probably means one thing- rust. Turn to cold, and see if your coloring problems still exist. If not, then it’s time to go tankless.
  • Water temperature drop- If the water isn’t heated as much as it should be (change in temperature), then you might search for a new heater.

What Affects the Age of a Heater?

There are a few things that can really make a difference between the tankless water heater and the storage water heater lifetime. Struggles that storage water heater has sometimes are affecting its lifespan. Those struggles are nowhere near the tankless water heater, and that’s one more reason for going tankless.

Water quality affects your storage water heater’s life, as it can wreak havoc and reduce its service by several years. With a tankless water heater, you should not worry about it.

Also, the location of a heater matters. Those water heaters that are positioned somewhere cold, where the temperature drops enormously, have to work much harder in order to heat up water. On top of it, they spend more electricity to keep it warm in their tanks. All of this affects the lifespan and can speed up the aging process by a lot.

Needless to say, tankless water heaters have no problems, no matter the position, which results in a much longer lifespan.

When it comes to the tankless water heater, there are some basic signs of it going old. Once you notice them, it’s time for a replacement.

Loss efficiency- Every tankless water heater can be overwhelmed. It all depends on your demands and how many appliances are running at the time. However, just put it on moderate demand, and if it seems like not keeping up, then it’s time for drastic measures.  Every time you notice that the heater can’t seem to keep up with the heating that previously wasn’t match for it, you know there’s something wrong.

A lot of repairs- It’s well-known that a healthy system demands repairs once or twice every few years. If you notice the difference, and you are constantly repairing your heater every few months, trust us- it’s better to replace the whole system rather than part by part.


As mentioned in the beginning, the lifespan of a tankless water heater is quite huge. In comparison to storage water heaters, it’s 2x or even 3x longer.

One of the reasons why you should go tankless is a lifespan. Depending on the quality, you will have from 20 years to 30 years lasting water heater. It’s quite a good investment, considering that you’ll need to replace it once or twice in your lifetime.

If we do the same math with storage water heaters, that’s around 5-6 replacements throughout the lifetime.

Hopefully, this article helped you realize how tankless water heaters are a good investment if we consider their long-lasting lifetime and all the benefits that they bring.

Leave a Comment

Your email address will not be published. Required fields are marked *