Find Discounts on Your Favorite water Products and Save Up To 20%!

Let's Go!

Are Tankless Water Heaters Loud? | Find Out The Facts

We may earn a commission if you click on a link, but at no extra cost to you. Read our disclosure policy for information.

Tim Rhodes

Before buying a water heater, you might have a question in mind, “Are tankless water heaters loud?”

There are many advantages of tankless water heaters over commonly used water heater with tanks.

They tend to be more energy-efficient, save space, and avoid the hassle of tank leakage.

Although tankless water heaters are less noisy than traditional water heaters, it’s a wrong idea that tankless water heaters do not make any noise while working.

With time your tankless water heater may get noisy, and there is a possibility that there is some technical issue causing that noise.

Either way, the wise decision is to get it checked so that you don’t have to go for the replacement of expensive parts and save money.

Are Tankless Water Heaters Loud?

Gas tankless water heaters can be as loud as 90 decibels when starting up and heating water.

Once your tankless water heater has finished heating water, it’s generally not very loud.

A decibel meter is recommended to find out just how loud your water heater is.

Let’s get into the details of the noise behind tankless water heaters.

Before we continue, check out these top-rated tankless water heaters that are extremely quiet:

EcoSmart ECO 27 Electric Tankless Water Heater, 27 KW at 240 Volts, 112.5 Amps with Patented Self...
  • Endless on-Demand Hot Water; Consistent hot water when you need it that never runs out; Continuously monitored water...
  • Save Space; EcoSmart tankless electric water heaters are 90% smaller than traditional tank heaters; may be installed on...
  • Save Energy; EcoSmart tankless electric water heaters are 99% thermal energy efficient; Only heats water when called...
  • EcoSmart ECO 27 Sizing; Refer to the sizing map. Requires 3x40 AMP Double Pole Breaker, 27-kilowatt tankless electric...
  • Warranty and Certifications; Limited Lifetime Warranty on electronics, exchanger and element; UL-499 certified; ETL...

Last update on 2022-09-27 / Affiliate links / Images from Amazon Product Advertising API

What Is The Average Level Noise Of Tankless Water Heaters?

If you’re going to buy a tankless water heater, you must be wondering what level of noise you should expect from its regular operation.

The most obvious and easy way to compare it with the loudness of the traditional water heater is that when the tankless heater starts heating water, it makes some noises.

It’s not something that you should worry about because it’s very reasonable for a tankless water heater to start its operation with that type of loudness.

It’s because they have burner and blower motor features, and the same elements are present in the heater with tanks as well.

But they keep the same level of noise throughout, whereas the tankless heater becomes less noisy once the constant temperature is reached.

Most people having the experience of both heaters do not report any significant difference between noise.

As per the reviews, the tankless water heaters do not go louder than your refrigerator.

It only reached the noise level of your refrigerator for a couple of seconds only when the flue-purge is working at its maximum speed.

With that said, a little noise that a shower makes in the next room can easily overwhelm the loudness of your tankless water heater.

This means that you’ll hear your tankless water heater working only by paying attention when no other appliances are running, no water is flowing, and it’s dead quiet.

There are some manufacturers of tankless water heaters in the market who praise and take pride in their products, how silent they are, and claim that it will not exceed 49db.

Mostly the best products that are most commonly used make noise that ranges between 45db to 65db, and that is a reasonable one.

Common Causes Of Noise

When sophisticated machinery operates, it makes all types of noises, and the same is the case with tankless water heaters.

It would help if you did not get worried whenever you hear sounds from your tankless water heaters because, as discussed above, all of them make sounds while working.

Even if your heater is not working, it can make noise, which happens due to the vacuum siphoning water that causes a little vibration and sound.

If you want to keep your unit working correctly then, you should call a plumber once in a while to check water line valves to avoid all types of problems that can cause damage to your unit.

There is a widespread problem that can cause harm to your device is the dirty flow sensor, and its work is to control the gas amount that the unit needs.

If the ventilation is improper or it’s somehow wholly blocked can easily cause unusual loudness.

Moreover, if the pressure is not set to the right amount or the sensor is defective altogether, then you’ll possibly hear a different type of noise.

You can check it yourself by using a decibel meter, and if the sound that your tankless water heater is making is more than 90 decibels, you need to get it checked from a professional.

If the sound is less than 90db, there is nothing to worry about, but you can still get it checked for your convenience.

You do not need any special decibel meter if you’ve got a smartphone because you can easily download any free app for a decibel meter.

Another common mistake that people make is the wrong installation of the heater, which can cause noise too when it touches the wall or other objects while vibrating.

Normal And Abnormal Noises That a Tankless Water Heater Can Make!

If you’re not into machinery and you’ve tankless water, you’ll hear many toes of noise.

If you want to know what types of noises are typical and which are abnormal, then continue reading to find out.

Tankless water heaters reduce the consumption of gas and electricity to keep a large amount of water warm in the tank, which eventually saves you money.

But the biggest concern about tankless water heaters is that they are installed inside your bathrooms instead of crawl space or basements.

On top of that they are noisy people usually are concerned about that so they come to the questions are tankless water heaters loud?

Below are some of the noises you should not worry about.

Normal Noises


If you can hear your tankless water heater clicking on and off and it does not continue for a long time, then it’s a typical sound that all the units generate while working.

It mainly comes when the unit starts or stops working because of the installed flow switch, which controls the flow of water.

Moreover, if the clicking sound is continuous while even without the demand for hot water, then at most, the flow switch is damaged, and you need to replace it with the new one.


Whenever you turn the hot water tap on, the initial ignition sequence usually is very loud, and many models can reach 90 decibels at that time.

The rumbling noise that you hear at that time is as loud as a jackhammer 50-60 feet away from you.

If you install your tankless water heater inside the insulated box, this sound reduces dramatically.

Still, if your unit makes the rumbling noise always, then you need to get it checked from a professional.

Abnormal Noises


If you’ve noticed your tankless water heater making groaning or moaning noise whenever you try to draw cold water by using an appliance near it, then probably your check valve is broken.

If the check valve is broken, then your unit will make groaning noise because it creates a vacuum problem with plumbing.

You need to keep in mind that cold water machines should not draw water from the water heater, but it’s entirely possible if the check valve is broken or not working correctly.


If you feel that there is a small gnome inside your tankless water heater and making a noise like knocking on the heater’s wall, then the most probable cause is that the pipes are banging with the outer body.

If the knocking sound comes whenever you start your heater and stops working, then it’s probably the same reason described above, and it’s also called water hammering.

The knocking sound travels through water and pipes and echoes in the whole structure of the heater, and you can fix it very quickly with a device that absorbs the shocks, which eventually causes awater hammer.

You can use straps as a stabilizer for pipes as well.


If any of the components of your tankless water heater is loose or free, it will vibrate while the unit operating can cause humming noise.

The heating unit in your tankless water heater is placed on one side of the whole body, and if any part or element of the heating unit’s loose, you’ll hear the humming noise.

Although there is nothing concerning and dangerous that you should be worried about regarding this sound, it can be irritating and annoying.

If you want to get rid of it, you need to tighten up any loose component, and that’s about it.

Most Popular Water Heater Accessories:

SaleBestseller No. 2
EcoSmart ECO 27 Electric Tankless Water Heater, 27 KW at 240 Volts, 112.5 Amps with Patented Self...
  • Endless on-Demand Hot Water; Consistent hot water when you need it that never runs out; Continuously monitored water...
  • Save Space; EcoSmart tankless electric water heaters are 90% smaller than traditional tank heaters; may be installed on...
  • Save Energy; EcoSmart tankless electric water heaters are 99% thermal energy efficient; Only heats water when called...
  • EcoSmart ECO 27 Sizing; Refer to the sizing map. Requires 3x40 AMP Double Pole Breaker, 27-kilowatt tankless electric...
  • Warranty and Certifications; Limited Lifetime Warranty on electronics, exchanger and element; UL-499 certified; ETL...
Bestseller No. 3
Kasa Smart HS100 WiFi Smart Plug, Classic 1-Pack, White
  • Control From Anywhere: Turn electronics on or off from anywhere with your smartphone using the Kasa app (Compatible w/...
  • Voice Control works with amazon Alexa, Google Assistant and Microsoft Cortana supported devices for a hands free...
  • Flexible Control: UL Certfied to switch upto 15A, for flexible control of a wide range of plug in devices
  • Kasa scenes & schedules: Schedule the Smart plug to automatically switch on and off when away or set a scene for...
  • Note: Requires a secured 2.4 gigahertz wifi network connection
SaleBestseller No. 4
Instant HEPA Quiet Air Purifier From the Makers of Instant Pot with Plasma Ion Technology, Rooms up...
  • ADVANCED AIR CLEANING TECH: Combines a HEPA-13 filter that captures 99.97% of dust, pollen, smoke, mold, & other...
  • CLEAN AIR IN MINUTES: Filters up to 1,940 SQFT per hour, and AHAM-Verified to exchange 388 SQFT 5 times per hour,...
  • AUTO MODE: Automatically senses the air quality and adjusts the fan speed according to detected quality. Digital read...
  • ODOR REDUCER: Activated carbon filter layer helps decreasing unpleasant smells, allowing your rooms or office space to...
  • WHISPER-QUIET: Light sensor automatically turns off displays and lowers noise to whisper-quiet levels when it is time...
SaleBestseller No. 5
Ecosmart ECO 8EcoSmart 8 KW Electric Tankless Water Heater, 8 KW at 240 Volts with Patented Self...
  • The product is highly durable
  • The product is easy to use
  • Manufactured in China
  • Heating elements are durable and are threaded for easy replacement
  • Activation Flow - 0.3 GPM

Last update on 2022-09-17 / Affiliate links / Images from Amazon Product Advertising API

Sediment Buildup

One of the most common and concerning noises that tankless water heaters make is sediment within the unit’s operational system.

Water that we usually use for our heaters contains many agents such as magnesium, calcium, etcetera, and water doesn’t stay for long in the system even then thesematerials can cause sediment.

As a result, you can hear several types of noises like hissing, popping, and cracking, and that can be dangerous for your tankless water heater.

When the hot water contacts with that sediment, it can generate popping sound, which happens because of the residue’s breaking.

Sediment is not something that will go away with the flow of water, so all the manufacturers and experts advise that you flush your tankless water heater every once in a while, with a regular cycle.

The average should be twice or thrice a year is more than a healthy practice, which will enhance the life of your unit.

But if you live in a region where the water is robust and contains more materials than you should flush your heater each month for better performance.

There is another method which you can opt for is to add a water softener with your heater.

Although it will not eliminate and filter out all the materials for good, it will enhance the performance, and it will take a long time for sediment to build up.

Understand The Workflow Of Tankless Water Heater

We are mentioning it again for your reminder that you should keep in mind that all tankless water heaters, whether they are brand new, make noises, and you should not get worried about all of them.

The workflow of the tankless water heater is effortless, and you need to go through the basics ofhow tankless water heaters workto know all the usual sounds that your heater generates.

The first step is to turn on the water tap connected with the heater for hot water, and the preinstalled flow sensor will detect the water flow.

When the water starts coming to the heater, the flow sensor sends its signals to the radiator to begin heating the water.

If your unit is gas-fired, then the control panel, after receiving the single from the flow sensor, will turn the fan on to let the gas in by opening the gas valve and drawing the air in which ignites the burner.

From those flames, the heat exchanger heats the water that flows from its tube and tempered by a mixing valve.

You receive the hot water that exits from the exchanger.

The water heats up according to the setting that you’ve given to the control panel.

If the waterfalls short or exceeds your desired setting, then the panel automatically adjusts the mixing valve and gas valve and water flow regulating valve according to the settings.

If you understand this process, then you’ll not only be able to identify each type of noise that your working heater makes, but you’ll also understand any abnormal noise.

Groundwater Temperature Matters For Better Performance And Less Knocking

There are several vital points to keep in mind while adjusting to or setting the temperature level of your tankless water heater, and there are various aspects that affect your product’s life.

If you increase the temperature settings to the last level of your unit, it will decrease your heater’s life.

The most important consideration is to know the temperature of groundwater where you live because it can have a significant impact on keeping the ideal temperature settings.

You can ask from experts, or you can search online to know the temperature of your area’s groundwater.

If the temperature is moderate or hot, you don’t need to worry about your heater’s ideal performance.

Still, if the temperature is colder, then it will be a little daunting for your unit to perform ideally.

Your heater will have to put more energy and heat to make water at your desired setting—the more temperature the heater is set, the less lifespan.

Moreover, it has been observed that tankless water heaters make less noise in those areas where the temperature of groundwater is moderate as compared to places with cold groundwater.

If the water in your area is cold, then what you can do is bore a little deeper to reach the moderate temperature level to enhance your heater’s performance and life.

What Is Standard Temperature Setting?

If we talk about the ideal hot water, there is no such thing because it varies from person to person, and it ultimately depends upon your desire.

As each person is unique, their physical structure and reaction to cold and warm are also unique, so they respond to the hot water differently, children and older people prefer more heated water than the young ones.

What you can do is set a temperature that works as a standard according to your household requirements, which in the normal conditions is 140F degrees.

That’s why most tankless water heaters also come with the same thermostat settings, which is also known as a universal standard.

But if you’re more concerned about the consumption of energy and your money, you should decrease that setting to 120F degrees.

Not only 120F is a safe temperature, and you do not feel much of a difference, but it also saves you a lot of money and energy drastically as compared to 140F degrees.

Reduced temperature also helps your heater prevent sediment buildup as more materials and minerals pass away with the water for good, and it also reduces the chance of corrosion.

On top of that all, less temperate also reduces the chance of all types of abnormal noises, and it can also save your money that you might spend on the maintenance, which will be mandatory if you keep your heater at a higher temperature.

Just that you know, whenever you decrease the temperature of your tankless water heater’s thermostat to 10F degrees, it saves you 5 percent of energy bills.

Although most water heaters come with the thermostat settings at 140F degrees, it’s not necessary to keep it with the same settings.

Advantages Of Tankless Water Heaters

There are manyadvantages of tankless water heaters, but the most prominent and famous one is that they are compact and take not too much space.

On the other hand, the traditional water heaters with tanks are getting bigger because, as per international standards, they must have thicker bodies and insulation.

If your house has an old construction, then new traditional heaters won’t be able to fit it where the same capacity old heater could.

If you own a vacation home and go there for once a year to spend your leisure time with your family, you must know how hard it’s to drain water from the heater with tanks before leaving.

Not only it takes a lot of time in draining, but it’s also a massive water wastage, and on the other hand, you need to unplug the tankless water heater, and that’s about it.

Another fantastic feature of tankless water heaters is that they are efficient and safe, and if there is a leakage, then don’t spill a massive amount of water as tank-type heaters do.

Moreover, the exhaust and the air supply vents are sealed adequately in tankless heaters, that’s why carbon monoxide can’t leak to harm anyone in your house because of back drafting.

There are a few things that you should keep in mind to get long-lasting and most efficient performance from your tankless water heater and avoid any unusual and abnormal noises.

If you do a little maintenance like cleaning up the sediment buildup, then the life and performance of your unit will automatically increase because the buildup can reduce the flow of water to approximately 0.3gpm, and your unit will shut off.

What’s Special About Tankless Water Heaters

It’s easy to contain and maintain tankless water heaters because they do not require a lot of maintenance to keep from harmful noises, which can also harm your product.

Besides, tankless water heaters do not keep the water hot in the tank because they are tankless, and you get the hot water instantly.

It takes about 10-20 seconds to heat water to your adjusted setting.

Some of the latest tankless water heaters come with WIFI, and you can adjust your desired temperature setting from your smartphone.

The most crucial feature that WIFI enables is that your unit can even identify the problem.

If it’s related to some lousy noise, then you can fix it yourself or call a professional plumber to perform his/her magic.

The top tankless water heaters on the market:

Last update on 2022-09-17 / Affiliate links / Images from Amazon Product Advertising API

Final Thoughts

Both of the extreme perceptions are wrong about the questions- are tankless water heaters loud?

– Because they are not the quietest, and they are not the loudest as well.

But what you need to do is to learn the everyday noises that we’ve discussed earlier so that you can differentiate between normal and abnormal sounds.

If you just cannot understand and explain what type of noise you hear, then call a professional to fix it for you.

You must keep in mind that some of the noises are normal and all the tankless water heaters can make them.

If you’re interested in buying the tankless water heater, then you should know all the discussed facts about their noise and other important features before.

If you already own a tankless heater, then get it installed by a professional plumber because the installation process in technical and wrong installation can cause many types of noises as well.

Furthermore, if you’re unable to recognize or understand the type of noises you hear from your unit, then do not try hit and trial or experiment, and just call a professional to repair or fix it.

In a Hurry?

Take a look at the most popular and trending water products.