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How Long Do Tankless Hot Water Heaters Last?

How Long Do Tankless Hot Water Heaters Last?

John Serrano
7 minute read

Tankless Hot Water Heaters are an efficient and space-saving way to heat water. But how long do tankless hot water heaters last? This article will look at the lifespan of a tankless water heater and what to expect of a typical unit after installation.

Expected Lifespan of a Hot Tankless Water Heater

The average lifespan of a tankless water heater is about 15 to 20 years. In most cases, tankless water heaters can last 20 years. If you take good care of your tankless water heater and keep it in good working order, it should last long without any problems.

Tankless hot water heaters utilize cutting-edge technology that keeps them intact and operational for much longer than other options. They are at the forefront of water heating innovation, with many newer models extending their lifespans well beyond the expected 20 years.

Extended Lifespan

The extended lifespans of tankless hot water heaters can be highly advantageous. Not having to replace a failing water heater for two decades provides both peace of mind and a lower total cost.

They are more efficient than tank water heaters because they only use the energy needed for heating the hot water required at any given time, rather than keeping all that hot water stored in the tank until it's needed (which would waste energy). 

This means that a well-maintained tankless water heater will use up to 70% less energy than traditional tanks.

Rinnai Tankless Hot Water Heater

Hot Water Heaters Have Easy-to-Replace Components

Should an issue arise with your tankless water heater before the end of its 20-year lifespan, it can typically be repaired relatively easily. Most repair parts for tankless water heaters are readily available, and regular maintenance can extend the heater's lifespan.

Please consider that some parts for tankless water heaters are more expensive than parts for tank water heaters, but they're straightforward to install, so experts won't have to spend much time resolving issues.

Tankless Water Heaters Have Fewer Corrosion Issues

A tankless water heater does not experience the corrosion issues generally associated with tank water heaters. This is because many problems with water heaters are typically associated with the tank itself, such as a leak, rust, or sediment buildup

Lifespan Impacts for Tankless Hot Water Heater

The following factors have a significant impact on the longevity of water heaters and should be carefully considered:

Pressure-Relief Valve

In conventional water heaters, you will find a pressure relief valve. These valves prevent the heaters from bursting due to an excessive pressure buildup within the water heater.

Perform routine inspections to ensure that your pressure relief valve is operating efficiently.

The Anode Rod

As previously stated, a conventional water heater's anode rod is its most crucial component. The anode rod is screwed onto the top of the gas/electric water heater. Replace it quickly if you observe any sign of corrosion.


Scale is detrimental to both tank and tankless water heaters. A small amount of limescale can make it difficult to heat cold water. The solution is to flush the heater with white vinegar that has not been diluted.

The processes for tankless and tank water heaters are distinct. For safety, follow the manufacturer's instructions.

Sediments Clogged

The sediments will clog the tank's bottom. Once or twice per year, you must flush your water heater to remove sediments.

Gas Lines

For a gas water heater, perform a monthly inspection to ensure the pipes are free of cracks and corrosion. You should contact a professional if you discover any signs of decay or damage.

Water Leaks

You may not notice a pipe leak or crack when your water heater is located outside. Nevertheless, a leak or puddle beneath your water heater indicates severe damage. If you discover a leak in your water heater, you should turn off the water and electricity supply and contact a plumber.

TwinTemp Junior Propane Tankless Water Heater

TwinTemp Junior Propane Tankless Water Heater


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Maintenance Tips for Tankless Hot Water Heaters

Inspect the pilot light, which is the power source for your tankless water heater. You need to replace the gas valve if it's flickering or not staying lit.

Suppose you have an electric tankless water heater or have had general problems with your electrical system. This is also an excellent time to check out your electrical outlet and ensure it's properly grounded.

Checking and adjusting pressure can help prevent damage to your gas lines due to high pressure and leaks caused by low pressure—both severe safety hazards.

A safe range for natural gas is between 6-8 PSI; if yours falls outside that range, contact a professional plumber who can help get things back under control before they become even more problematic than they already were (and possibly dangerous).

Ensure all vents are clear, so no moisture builds up inside them, especially during winter when air temperatures drop below-freezing levels for extended periods.

Replace anode rods about every five years, depending on how much use it gets (this depends on the location of it too). Over time, these rods protect against corrosion from highly acidic water passing through metal pipes within tanks.

If they aren't replaced regularly enough, these pipes will eventually corrode completely, destroying any chance of using them again without replacing them entirely first (which isn't cheap).

The Make of a Tankless Water Heater

A traditional tank is made of thin steel that rusts easily and must be replaced every 5-10 years. A tankless unit has no moving parts, so there's no need for any maintenance or replacement during its lifespan.

Tankless systems are more expensive than traditional storage tanks. Still, they pay for themselves over time with savings in energy costs and an environmentally friendly design (no additional energy is used while waiting for hot water).

Tankless units have longer lifespans than their traditional counterparts because the heat exchange device inside does not deteriorate quickly over time due to extreme temperatures and pollutants in the air surrounding them (like steam).

So, How Long Will Your Tankless Water Heater

If you're looking to buy a tankless hot water heater, you'll want to know how long it last. Tankless water heaters can last 20 years and reduce energy use, but they require careful attention.

Ensure you can do some things so that your tankless hot water heater lasts for more years. Be sure to have it installed by a professional plumber who knows what they're doing, so they can install it correctly and get the most out of your investment.

If you're looking for a tankless water heater, feel free to check out our collection of tankless hot water heaters or shop by brand with Rinnai, Eccotemp, or PrecisionTemp

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