How Long Does a Tankless Water Heater Last?

How long does a tankless water heater last?

  • Maintaining your water heater usually helps ensure its longevity. But how long does a tankless water heater last? This article explores all the possible variables that affect the lifespan of a water heater.

Let’s face it; this is the furthest we’ve ever been from traditional appliances. We now count on modern appliances for most of the things that go on around our homes. Whether it’s a cooking range or a refrigerator, we rely on the sleekest designs or the most cutting-edge features, and this only shows that we now live in the future we foresaw many years ago. A tankless water heater is one of these convenient appliances. The big question, however, is, ‘How long does a tankless water heater last?’

The water heater has become a crucial part of every home. It helps constantly supply hot water; the better part is when you opt for the tankless one. Also known as “on-demand,” tankless water heaters only provide hot water when needed. This makes make them more energy-efficient than their traditional counterparts. Like every other appliance, maintenance is a big part of keeping your tankless water heater at a premium bay. In this article, we’ll explore how long a tankless water heater lasts and how you can keep it functioning at the highest level for a long period.

How Does a Tankless Water Heater Work?

Every appliance has a touch of mystery to it. You must have wondered; how does a tankless water heater work? How do you turn on your water faucet and have hot water flow through? The magic behind it is pure technology.

As soon as you turn on your water faucet, cold water flows through the pipes and gets to the tankless water heater. Depending on the type, the tankless water heater is usually powered by a gas burner or an electric element. This helps heat up the water in the tankless water heater before it is sent to your faucet. Hot water travels through the pipes again and is distributed to your faucets.

Unlike a traditional tank-style water heater that stores hot water and re-heats, a tankless water heater only produces hot water on demand. You get hot water whenever you need it, and that’s what makes a tankless water heater so efficient.

This is a big advantage over a tank-style water heater. With a tankless water heater, you can save a lot of money on energy bills while prolonging the unit’s life because it’s not always in action and only produces hot water when needed.

The Lifespan of a Tankless Water Heater

The United States Department of Energy predictably sets the lifespan of most tankless water heaters to around 20 years. This is nearly double what a tank-style water heater can last, making the former a great investment, especially considering the long term.

One of the many things a tankless water heater is popular for is its energy efficiency. This is what gives it an edge over the old-school traditional water heater. However, a tankless water heater may not last that long due to some factors, most importantly maintenance. Some of these factors also include:


This one is simple – the more you use the tankless water heater, the harder it works, and when an appliance functions that hard, it’s only a matter of time before it begins to wear out. Usage is an important factor in determining the longevity of a tankless water heater. If you have a large family and there’s a high demand for hot water, you can’t compare your water heater’s lifespan to a family of two.

Water quality

Like usage, water quality is another thing that can affect the lifespan of a tankless water heater. The funny thing is that the impact can be significant, especially when you live in an area with hard water. Over time, hard water produces a high volume of minerals like magnesium and calcium, which can eventually corrode the tankless water, damaging it if not properly maintained. The only way to ensure longevity in this situation is to have a strong maintenance plan and stick to it strictly. Regular maintenance will help keep the tankless water heater free of mineral deposits.

Model and manufacturer

Tankless water heaters are not created equal. Model and manufacturer also play a huge role in the lifespan of a tankless water heater, and this is because these manufacturers have different recipes and ideas of how they want their tankless water heaters to be. This is why you should aim for the best quality possible. It will come at a great cost, but if you want to use it for a long time, it’s a small price to pay.


The most important of them all – maintenance. Even if you don’t have a quality tankless heater for water, regular maintenance is one way to keep it longer than usual. It’s like a cheat code – as long as you can take care of the unit, you should be able to get some good years out of it.

Signs Your Tankless Water Heater Needs Replacement

This is a tricky one. Sometimes, your unit only needs to be replaced, but you’ll think it needs a replacement, and vice-versa. If you haven’t used the unit for a long time, you should consider repairing instead of replacing it. However, if you’ve been using the unit for a long time, it’s only normal that it starts showing some signs of wear. Below are some signs your unit needs to be replaced:

Inconsistent water temperature

The single task a water heater has is to provide hot water. A tankless water heater has to provide hot water on demand, so when you start getting inconsistent temperatures, it might be time for a change. Inconsistent water temperatures might be a sign that your water heater needs to be repaired or replaced. As we pointed out earlier, if you haven’t used the unit for a long time, you should consider repairing it instead of replacing it.

Frequent breakdowns

This is very common among old units. When a water heater has passed its peak, it will break down more often. This indicates the unit is near its end, which means you have to start preparing to replace it with a new one as soon as possible. If you don’t, you’ll just keep spending money on repairs, which won’t solve the problem for long.

Old age

Every good thing eventually has an end, sadly. That applies to your water heater as well. Even if it’s the most efficient and durable unit, old age will kick in and start to wear. Once you notice some signs like inconsistent temperatures or constant breakdowns, you should start making plans for a replacement.

Increased energy bills

Tankless water heaters are popular because they’re more energy-efficient than their traditional counterparts. Once your tankless unit starts consuming more energy than it should, it indicates a fault that needs to be addressed as soon as possible.


Tankless water heaters are great and durable, but like every other appliance, they have a lifespan, and it will save you a lot of stress to prepare for it. How long does a tankless water heater last? Well, as stated throughout this article, it depends on many factors. However, the average is usually around 20 years. Don’t forget to watch out for the signs, especially when a unit is nearing its end. Also, always prioritize regular maintenance because this is one of the most effective ways to extend the lifespan of your tankless water heater or at least get it to last for as long as possible.

Frequently Asked Questions

How does the lifespan of a tankless water heater compare to a traditional water heater?

According to the Department of Energy, a tankless water heater usually lasts for about 20 years, while a traditional water heater lasts about 10 years.

What factors can affect the lifespan of a tankless water heater?

Maintenance, water quality, old age, and usage are some of the factors that can affect the lifespan of a tankless water heater.

Can the type of water in my area affect the lifespan of my tankless water heater?

Yes, very possibly. Hard water has a high volume of mineral deposits, which can build up in your unit over time.

Is investing in a quality tankless water heater for a longer lifespan worth it?

If you invest in a quality water heater without maintaining it, it’s only as good as its last run. Investing in a quality tankless water heater and having a strong maintenance plan can extend its lifespan.

What are the signs that a unit needs to be replaced?

If you’re not getting the value for your money again, something is wrong. A tankless water heater is supposed to be energy-efficient, durable, and consistent. If you’re not getting that, a change needs to be made.