Best Under Sink Water Heater For Kitchen Sink And Dishwasher

Beginner Info, Tankless Water Heater

best under sink heaters
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Are you on the lookout for the best under-sink water heater?

Well, in this post, I would be walking you through some of the best under sink heaters available on the market, right now.

Moreover, I’ll also be throwing light on various aspects of an under sink heater in order to help you make an informed buying decision.

Lastly, I would be responding to the queries related to sink heaters review so that most of your doubts are cleared if NOT ALL.

But, before that, I would be needing a small help on your end.

Would you be interested in helping me?

In case, you’re planning to go with the wind, and your answer is “YES”, then all you need to do is to respond to a couple of queries.

Does it make sense?

So, which is your favorite under sink water heater brand?

How much are you willing to spend on your brand?

Furthermore, how often do you read product reviews before buying a product?

Enough of questions, right?

So, without any further ado, let’s begin…

Top 3 Under Sink Instant Hot Water Heater Comparison Chart

 ProductEditor’s CommentVolume (gal) Voltage (V)Recovery Rate (GPH)Temp Range (R) Weight (lbs) Dimensions 
EcoSmart ECOBest for Energy EfficiencyN/A240 280-140 6.511.5″ * 8″ * 3.75″
Thermoflow UT10Best for Colder Regions 2.6 120 2.645-167 1418″ * 12.2″ * 11″
Ariston GL6 +SBest for High Hot Water Demands 6+120 6.8 65-145  29.517.5″ * 17.5″ * 14.5″

Best Under Sink Instant Hot Water Heater Review

Before we dive deep into the discussion, please allow me to explain to you the process that we follow for shortlisting the products.

In this case, the product is under a sink water heater.

First and foremost, our core team does the brainstorming and comes up with a set of evaluation parameters.

Each of these parameters is assigned a certain weightage depending upon its ability to influence a buyer’s decision.

During the evaluation, products score certain marks across the evaluation parameters depending upon the performance.

Finally, we consider the cumulative score for shortlisting the products.

In case, you’ve any doubt or query then feel free to contact us, and we would be more than happy to assist you to the best of our capabilities.

Cutting long-story-short, let’s get back straight to the topic.

Well, if you’re like me who dreamt of upgrading the current water heater but the big expense is keeping back, then trust me, you’ve landed on the correct post, indeed.

As the name suggests, under sink water heaters are small and compact, and are known for providing hot water instantly on-demand.

These little beasts are equipped with idiosyncratic features as well as superlative technology in order to help end-users like you and me to achieve an optimum result.

EcoSmart ECO 11 Tankless Water Heater

Frankly speaking, the brand EcoSmart is my favorite when it comes to buying an electric tankless water heater.

I’m so much fascinated with the aura of this brand that I bought a couple of models including ECO 27.

Trust me, all the variants of EcoSmart are equipped with advanced technology and premium features so that you can reap maximum benefits.

However, we would be concentrating today’s discussion on the under-sink model of the brand EcoSmart which is supposed to be none other than EcoSmart ECO 11.

I would like to start with a piece of good news, and of course, it will grab your eyeballs too.

Can you guess?

Well, the brand offers you a lifetime warranty on not only the exchanger but also electronics and elements.

However, the warranty doesn’t cover labor or any incidental damage.

Moving further, the 13-kilowatt tankless electric heater is ideal for not only the sink but also a bathroom, office breakroom, and other point-of-use applications.

In fact, the flow rate of hot water provided by this little beast can vary between 1.3 and 3.1 gallons per minute which depends upon the inlet water temperature.

In simple words, the colder the region the less will be the flow rate.

However, even in the worst circumstances, the unit will support at least a sink for sure.

With the help of the built-in digital temperature control, you would be able to control the unit in a much better way as it allows you to set the temperature in an increment of 1-degree.

As compared to a convention tank, this EcoSmart model claims to save a lot of space, in fact, up to 90 percent because of its small, compact, and sleek design.

And, the best part is, the unit is equipped with the most advanced self-modulating technology which ensures that energy is only consumed when there is a demand for hot water.

As a result, there isn’t any standby loss, and thus, efficiency surges.

According to DOE, the EcoSmart tankless electric heaters can save you up to 50 percent on water heating costs which are definitely something to brag about, isn’t it?

I hope till now you would have understood why EcoSmart Eco 11 is my favorite on this list.

Trust me, the unit is a unique blend of quality, efficiency, reliability, convenience, usability, and of course, performance.

Do I still need to convince you?


  • Can save you up to 50 percent on water heating bills
  • Small, compact, and sleek design
  • Lifetime warranty
  • Equipped with advanced technology and idiosyncratic features
  • Newbie friendly installation process


  • EcoSmart Eco 11 might not be the best choice for very high water demand in cold climatic conditions

Thermoflow UT10 2.6-Gallon Mini-Tank Water Heater

Frankly speaking, some of my clients have faced an issue with using underskin heaters in cold regions.

I totally agree with their claims and its fact that quite a few models that are cheap aren’t as effective as the ones that we’re reviewing.

One of the reasons for us to explain to you the entire shortlisting process in simple words is to gain your confidence and trust.

We try to the best of our capabilities to do things the correct way.

And, the Thermoflow UT10 isn’t an exception at all.

As per my knowledge and experience, this little beast will match up to your expectation if NOT EXCEED.

Time and again, the unit has delivered in the climatic conditions effortlessly.

So, if you’re looking for an under-sink heater for a colder zone then there is nothing wrong with trying Thermoflow UT10.

The unit comprises a stainless steel tank that makes it durable and long-lasting.

It will provide you with hot water instantly without putting you on a wait.

Moreover, the unit is equipped with advanced thermos top technology of Germany that is meant to stop the device automatically when it approaches the set benchmark for temperature.

Needless to say, the unit is idiosyncratically designed to minimize standby loss.

With the help of innovative technology and better insulation, the unit not only reduces the long wait hours for hot water but also helps in maximizing performance.

Trust me, you don’t have to worry at all about your kids and pets, as the unit is completely safe to use.

In fact, the water heater comprises safety features including overheating protection, auto cut-off electricity, etc in order to help end-users with the best possible protection.

I know most of you would be well aware of the auto cut-off protection feature present in a water heater.

However, if you’re new to it then please allow me to explain it to you.

What actually it does is, automatically cuts off the electricity supply to prevent the water heater from getting overheated.

And, as a result, the risk of damage to the water heater reduces drastically.

Moreover, installing the unit isn’t a time-consuming task at all.

In fact, all you need to do is to plug into the electric supply socket, then tap into the cold water lines.

And, finally, install the water heater directly at the sink so that you can get hot water instantly without any hassle.

If you’re planning to buy it for a colder region then let me tell you, the unit comes with a frost protection feature that protects it when the temperature starts falling rapidly.

The energy-saving mode will help you to save a good amount on electricity bills for sure.


  • Frost protection mode
  • Stainless steel material
  • Energy efficiency
  • Small, compact, and uniquely designed


  • Some standby heat losses is bound to be there

Ariston GL6+S Electric Water Heater

The Ariston GL6+S is definitely one of my favorites in the electric water heater category, and trust me, there are numerous reasons for it.

In fact, my husband and I had an altercation before I brought this little beast home.

His preference was a different model that doesn’t even make to our list.

Anyways, cutting long-story-short, let’s have a quick look at the things that made me think that it’s a superlative product. indeed.

Just for your information, we’ve 3 offices so we’ve installed a couple of water heaters, and each model and brand is different.

BOSCH is definitely a well-trusted and well-established brand that doesn’t need any introduction.

And, the Ariston GL6+S matches the expectation that most of us have from such a premium brand.

It’s a beast in the true sense, not only is it powerful but also capable of providing enough hot water for a big family.

With a 6+ gallon water tank and measuring 14.5 inches by 17.5 inches, the unit is bound to deliver high-performance and instant hot water.

Installing the unit will not consume much of your time, and irrespective of you being a first-time buyer can expedite the entire process on your own.

All you need to do is to place it under the sink, then connect it to the water pipe, and finally, plug it into standard output.

And, for the better reason, it is also equipped with a glass-lined tank which minimizes the heat loss to the environment.

Lastly, the electric water heater is backed by 6 years warranty which clearly depicts the trust and confidence of the brand in its offering.

To be honest, it takes a lot of time and effort to achieve the feat that the brand BOSCH has achieved.


  • 6-year warranty
  • Newbie friendly installation process
  • Best for high hot water consumption scenarios


  • Takes relatively longer for providing hot water

ATMOR AT-900-03 0.5 GPM Sink Aerator

So, here I come with yet another high-quality under sink hot water heater which is not only equipped with high-quality idiosyncratic features but also advanced technology in order to help you achieve an optimum result.

Frankly speaking, I’ve received some extremely positive feedback from my clients which clearly depicts the interest of my clients in this particular product.

Definitely, this little beast is gonna play a crucial role when it comes to saving money, water, and energy.

However, it is my responsibility to update you that the unit is specifically designed for hand washing single sinks in areas with at least 57 degrees Fahrenheit groundwater temperature.

On the downside, the unit might not be the best choice for the northern regions with the inlet water temperature colder than 57-degrees.

Moreover, in order to achieve a 45-degrees rise in temperature, you would be needing a flow rate of 0.5 gallons per minute.

In order to achieve the maximum outcome and prevent any last-hour misadventure, you must ensure that the heater is installed by a licensed electrician in compliance with all local and building regulations.

It goes without saying that the unit comes with all the essential features that make it highly suitable for both residential as well as commercial uses.

In order to reap maximum benefits from the warranty, you need to comply with the installation and operating instructions clearly mentioned in the owner’s manual.

Moreover, the installation of a 0.5 GPM sink aerator will definitely help you in enhancing the performance.

To sum up, if I’ve to put it in one sentence, all I can say is ATMOR AT-900-03 is one of my favorite under sink hot water heaters for sure.


  • On-demand endless hot water
  • Energy efficient
  • No venting required
  • Eco-friendly


  • No plug-in

WaiWela WM-2.5 Mini Tank Water Heater

So, here I’m with yet another high-quality mini-tank water heater that is bound to grab your eyeballs.

Since the tank is glass-lined so you can expect it to last longer.

Not only does the unit comes with an attached power cord but also, adjustable thermostat.

Moreover, the WaiWela WM-2.5 Mini Tank Water Heater comes with overheating protection to prevent any mishap due to an uncontrolled surge in temperature.

It also comes with a wall-mount option which could be of great help in the case, you want to free up the floor space.

The 18 lbs heater is backed by 6 years of limited warranty on tank and 2 years on parts.

Furthermore, the unit is equipped with advanced technology that reduces the hot water wait time to a large extent.

The installation process is quick and easy and could be a great fit for a single sight.

All in all, the little beast is worth the time and investment if you’re looking for a hassle-free way to get instant hot water.


  • Easy installation under sink
  • Overheat protection feature
  • Smooth electric insulation
  • Robust and durable construction


  • Temperature fluctuations need to be handled with care

Bosch Electric Mini-Tank Water Heater Tronic 3000 T 

The Bosch Electric heater comes with a 2.5-gallon point-of-use mini-tank that can fit easily under the sink and can provide you instant hot water without any hassle.

Moreover, the unit claims to have 98 percent thermal efficiency which is definitely one of the best in its class.

The tank comprises glass-lined material and as a result, you can expect the unit to last longer.

Similar to other premium heaters, it is also equipped with advanced technology that reduces the wait time for heat water drastically.

The Bosch Tronic 3000 T comes in three sizes, and depending upon your requirement, you can choose from 2.5, 4, and 7 gallons mini-tank.

Without any doubt, the unit could be a great fit for RVs, boats, kitchenettes, and patio sinks.

In order to help you achieve maximum energy efficiency, the manufacturer has inculcated thick CFC-free foam insulation.

Of course, it can be installed easily in small spaces, and the credit goes to the small, compact, and sleek design.

Lastly, the 3000 T is backed by a 6-year warranty on the unit and a 2-year warranty on parts.


  • Capable of serving hot water to two sinks simultaneously
  • Lightweight, compact, and durable
  • Temperature relief valve included
  • One of the best in its category
  • Glass lined-tank to ensure longevity


  • Self-installation can be a time-consuming affair especially for the first-time buyers

Reliance 6 2 SSUS K 2.5 Gallon Electric Water Heater

The 20 lbs Reliance 6 2 SSUS is not only equipped with advanced and idiosyncratic technologies but also possesses UL certification.

Moreover, the Series 606 electrics provide up to 4,500 watts per hour input which according to me is sufficient for a small-sized home hot water requirement.

Trust me, the unit is capable enough to provide you instant hot water by drastically reducing the wait time.

The unit is portable and the installation is simple and easy.

Like the other premium under sink hot water heaters that we’ve discussed so far, the Reliance 6 2 SSUS also comes with a durable stainless steel tank.

It’s definitely one of the best mini instant water heaters under the sink for small sinks and single application uses.

Lastly, the unit is backed by 6 years of warranty which clearly depicts the trust and confidence of the manufacturer in its offering.


  • 2.5-gallon tank, no wait time for hot water
  • Durable, stainless steel design
  • 6-year warranty
  • Small, compact, and portable


  • The power cord is short so you might be needing an extension if your plug is far away

InSinkErator H-HOT150SN-SS 

The InSinkErator HOT150 Instant Hot Water Dispenser System is the newest and most affordable addition to the invite series, and of course, for good reason.

Moreover, the HOT150  comes with an easy-to-adjust thermostat that helps you with better control when it comes to setting the temperature in the range of 160 degrees F and 210 degrees F.

The unit is newbie friendly and comes with a DIY installation without any requirement of special plumbing.

Furthermore, the 7 lbs InSinkErator comprises metal and plastic materials and is certified frustration-free.

The manual that it comes with covers almost all the essential pieces of information related to installation and other related things.

It also provides you with tool-free tank connections and dry start protection which will definitely, ease your installation process.

And, the best part is, you’ll get a year warranty that includes free house calls for both parts and labor.

In simple words, if you own a small house then the unit will definitely suffice your hot water requirements as it is capable of delivering up to 60 cups/hour of 200 degrees Fahrenheit.


  • Easy do-it-yourself installation
  • You have got an option to set the temperature higher than other models
  • Provides instant boiling water
  • Comes with a satin nickel hot water dispenser


  • Lower holding capacity of 2/3 of a gallon

Camplux ME25 

Well, the Camplux ME25 is definitely one of the best portable sink water heaters that I’ve come across.

Moreover, it allows you to get easily instant hot water at your sink.

The unit is highly cost-effective and will save you both time and money.

Since the unit is equipped with advanced technology so you don’t have to wait longer for the hot water.

The gas-lined tank not only provides great insulation but also comes with a low maintenance cost.

With the 2.5 gallon tank, the unit holds enough hot water for your day-to-day requirement.

In fact, the unit will suffice the hot water requirement of a small apartment, office, or a single-use that might be far away from the main water heater.

Other than the apartment, you can use it for both RV and boat.

It also constitutes some great safety features including overheat protection which will set the unit off in case it goes above the set temperature and pressure relief valves.

In case, you’re planning to buy the Camplux ME25 for a cold climatic condition, then the freeze protects unit would be of great help when it comes to protecting the unit against the freezing threat.

In simple words, the unit is a unique blend of high-quality, performance, and safety.


  • Easy installation and low maintenance
  • Small, compact, and sleek designed
  • You don’t need any extra wiring, all you need to do is to plug-in
  • Equipped with extra safety features such as temperature control and pressure relief valve


  • Some of my clients haven’t liked the design

Best Under Sink Instant Hot Water Heater Buying Guide

In this section, we would be discussing some of the important parameters that you shouldn’t overlook when it comes to buying an under sink hot water heater.

Unit Size

Definitely, the first thing that comes to my mind when it comes to buying a highly efficient under sink water heater is the size.

You must be well aware of the size that you’re looking for.

In simple words, knowing the amount of space that a unit requires and the room you’ve available will definitely decrease your hassle.

Don’t buy any model without checking its dimensions and ensuring that whether or NOT it will fit well under your sink.

By doing so, you’ll mitigate the risk of ending up buying a unit that is too big for the space that you’ve.


Well, if you’re going to go with a unit that has a tank, then be aware of the amount of water that the unit has the capacity to store.

We’ve reviewed certain models that come with the options in tank size.

Look for a larger tank if you’ve got a medium or large-sized home.

Flow Rate (GPM)

Frankly speaking, the flow rate is measured in gallons per minute.

In simple words, the higher the flow rate a water heater has the more quickly it would be able to heat the water.

For example, 1 GPM means the unit would be able to heat roughly one gallon of water per minute.

Moreover, if your hot water requirement is huge then you must look for a higher GPM.

Most of the tankless hot water heaters have flow rates falling in the range of 0.5 and 2.25 GPM.

Heating Power in kW

Well, heating power simply means the amount of power that the unit would be needed to heat the water.

Units with a smaller kW power won’t be able to heat larger quantities of water quickly.

In simple words, how much kW you would be needing totally depends upon the temperature level you want to heat the water.

You can expect a higher increase in temperature as well as water heating at a faster rate in case, you’ve opted for the unit with a higher kW.

What I’ve discussed so far is related to tankless hot water heaters.


Voltage is nothing but the electric requirements that are needed to power the unit.

It is solely your responsibility to ensure that the electric outlets that you’re using can handle the voltage of the water heater.

In fact, most of the units can be easily plugged into 120v outlets.

However, I’ll not deny the fact that there are models that require 220v.

What I mean to say, you might have to make the adjustment to your outlets.

Energy Efficiency

Well, under sink heaters are more energy-efficient as compared to other models as they don’t waste a lot of energy heating as well as storing a large amount of water.

Simply by checking the energy efficiency rating of any unit, you’ll have a rough idea about the efficiency.

In fact, most of the units offer 96 to 98 percent energy efficiency ratings that simply means they cut down on a significant amount of energy loss.

Recovery Rate

The recovery rate is nothing but the gallons of water a particular unit can heat.

If I’m not wrong then the standard is usually raising the temperature by 90-degrees Fahrenheit in an hour after being completely emptied.

The recovery rate is measured in gallons per hour.

In simple words, if the recovery rate for 90 degrees Fahrenheit temperature rise is 6.8 GPH then it simply means that the unit is capable of heating 6.8 gallons to 90 Fahrenheit in an hour.

In layman’s terms, the higher the recovery rate the more quickly will the hot water get replenished.

This is only used for the water heater models that come with a tank.

Safety Features

Frankly speaking, almost all the units that we’ve reviewed are equipped with safety features, and as a result, these units are safer and easier to use.

Moreover, some units do come with a built-in thermostat making the regulation of the water not only easier but also less time-consuming.

Another important safety feature is modulation, which simply means that the unit can easily change the heat output in response to the flow rate of water running through the unit.

The benefit of it is that the water temperature is better kept regulated no matter what the flow rate is.

A pressure relief valve is another important safety feature to look for which prevents damage from happening due to excessive water pressure.

In case of very high pressure, the valve relieves the pressure making it safer for use.

Installation and Maintenance

It goes without saying that the different types of units will require different kinds of installation and maintenance.

Some models can simply be plugged into an outlet and ready to use, while others will require more electrical or plumbing work to be operational.

Furthermore, most of the units can be installed by you.

However, my advice would be to hire a certified professional if you’re planning to buy a complicated model.

Needless to say, you must read all the installation and maintenance requirements before and after purchase.


Needless to say, price is an important influencing factor when it comes to buying any product not only under sink heater.

Always look for products that not only cater to your needs but also fall well within your budget.

Trust me, the costliest aren’t always the best and the cheapest aren’t always the worst.


The more the warranty duration the better it is.

Always look for products that come with a longer range of warranties.

There are loads and loads of units that offer a tangible duration of warranties.

However, they may require that the unit has been installed by a professional in order for the warranty to be valid.

What are under sink water heaters?

Well, under sink water heaters are the ones that are small, compact, and sleek designed and are mainly mounted under a sink to supply hot water directly to the faucet.

They are also popularly called point-of-use water heaters.

There are mainly two types of under-sink heaters, the first ones are those that heat the water while it passes through the unit, and the second ones are those that store a small amount of hot water in the tank that comes with the unit.

Trust me, you don’t always need an under-sink instant hot water heater for sure.

So, the question arises that when should one buy it, right?

If the main water heating system is located far away from a particular faucet resulting in taking a good amount of time to provide hot water through that faucet, then you can get rid of the wait time by installing an under sink heater.

Another scenario is when the demand for hot water is more than the capacity of your heater and you don’t want to upgrade to a more powerful and larger unit, then the additional load can be handled effectively by the under sink hot water heater.

In other words, installing these little beasts will help you in saving money on your energy bills as well as lowering your energy usages.

Under Sink Hot Water System Types

There are mainly two types of under sink hot water heaters, that is, tank, and tankless systems.

Let’s have a quick look at each one of them.


A first option is a tank-based unit that heats up a small amount of water in advance and keeps it for future use.

Mostly tank-style models hold water in the range of 2.5 and 7 gallons at a time.

Definitely, it’s a great option if you want to have hot water instantly.

On the other hand, it also helps you in cutting down on water usage as you don’t have to run your sink waiting for the hot water to get there.

You can easily plug such units into a standard electric outlet, and are definitely easy to install for sure.

This type of model could be a great fit if your faucet is located far away from the central heating system.

Or, places where you need instant hot water in small quantities.


Another option that we’ve is a tankless water heater.

The best thing about the tankless water heaters is that you don’t have to store hot water so standby losses would be negligible.

In fact, in the tankless water heater, the water gets heated by the electric filaments as it passes through the units.

And, the best part is, you’ll get an endless supply of hot water effortlessly.

The heater will only consume power when it will detect the water running through it.

On the contrary, a conventional water heater runs constantly in order to keep its tank of hot water.

Needless to say, the tankless version is small and compact and occupies comparatively less space because of its sleek design.

But, at the same time, the unit will require a bit more setup than a tank-style heater.

You need to ensure that you hook up the wiring and connect it to the existing pipe properly to ensure that it works perfectly.

Once installed, it will definitely reduce your water heating cost without compromising on efficiency.

Benefits of Under Sink Hot Water Heater

Well, there are quite a few benefits of using an under-sink hot water heater.

Let’s have a quick look at each one of them.

Compact Size

As discussed earlier, under-sink hot water heaters are small and compact.

In fact, these units will not consume much of the space and can be installed under the sink.

Needless to say, these little beasts are way smaller than the conventional hot water heaters.

Easy Installation

To be honest, you don’t require a lot of electronic or plumbing knowledge to set up the unit.

Irrespective of you being a newbie or a seasoned professional, the installation will not consume much of your time.

On top of it, almost all the units that we’ve reviewed in this post come with instructions and easy-to-follow guides that make the entire installation process less time-consuming and hassle-free.

Fast Heating Time

You don’t have to wait for hot water as these units can heat water rapidly and instantly.

In most cases, you’ll not find any time lag between turning on of faucet and the flowing of water.

In other words, you don’t have to the wastewater by allowing it to run until it gets hot.

Constant Hot Water Supply

No need to worry about running out of hot water when using an under-sink hot water heater.

And, as a result, these units are a preferred choice for showers, bathtubs, and kitchen sinks.

Energy Efficient

The system will do the trick for you when it comes to cutting down on your household energy consumption because they require less energy to heat up the water.

Of course, they aren’t constantly running to keep a large amount of hot water.

Under Sink Hot Water Heater Maintenance

It goes without saying that you must keep your under sink water heater in good health in order to reap maximum benefits out of it.

Similar to any other water-based appliance, the under sink heater also comes with the risk of developing limescale buildup so it’s always advisable that you flush your heater at least once a year if not MORE.

Let’s have a quick look at some of the routine maintenance tasks that you need to run.

  • Regular flushing out of your under the sink water heater
  • Checking pressure relief valves on a regular basis
  • Also, checking periodically for leaks
  • Checking thermostats and regulators are working properly or NOT
  • Checking all hook-ups are tight and secure

Even though you’re a first-time buyer, you’re capable enough of doing these maintenance checks on your own.

However, if you have got a scarcity of time, then my suggestion to you would be to hire a professional to do the job for you.

How to install an under sink water heater?

As we discussed earlier, installing an under sink water heater depends to a large extent on what type of model you’ve opted for.

For example, installing a tankless water heater would be slightly different from a tank-styled water heater for sure.

Nonetheless, as a whole, installing a POU water heater is relatively easy and quick for sure.

Either you can install it on your own or you can even hire a professional for this purpose whichever suits you.

Nevertheless, if you’re not used to or don’t feel comfortable with electric and plumbing work then my suggestion to you would be to hire a professional.

At the same time, you also need to be aware of the fact that certain companies only offer warranties when the installation process has been expedited by a certified profession so you need to act accordingly.

Tank Water Heater Installation

  • First and foremost, you need to ensure that enough room is present under the sink for the installation of the water heater
  • Turn off the water supply to the sink
  • Mount the unit on the wall, shelf, or even floor depending upon your requirement
  • In the next step, you need to tap into the hot water link under your sink by connecting the tube on a heater to the tube running to your faucet
  • Plug the unit into the wall outlet

Tankless Water Heater Installation

  • First and foremost, you need to mount the unit on the wall
  • Connect the water source to the inlet side of the unit
  • Moving further, you need to connect a pipe to the outlet fitting on the unit
  • Moreover, you need to ensure that all the plumbing is hooked up correctly before moving onto electrical, run the water
  • Depending upon the type of unit that you possesses, you need to ensure that you’ve got the correct wiring
  • Connect the wires to the unit and then connect the other end of the wires to the circuit breaker

Note: Especially with the tankless units, the installation process can be expedited on your own if you’ve got some idea about plumbing.

However, hiring a professional would be a better choice, indeed.


In this section, I would be responding to the questions related to under sink water heater review in order to help you make an informed buying decision.

So, without any further ado, let’s begin…

Do I need a licensed plumber to install an under sink water heater?

Well, it’s not required but if you’re not comfortable with expediting the installation process on your own then definitely, you need to opt for a certified professional.

Moreover, some units require the installation to be done by a professional in order to avail of the warranty.

How does an under sink hot water heater works?

A under sink hot water heater is located in the vicinity of a water outlet such as a faucet, in order to help you with instant hot water.

If you’re using a tank-styled under sink hot water heater then it will have stored hot water for your use.

On the other hand, if you’ve bought a tankless device, then it will heat the water as soon as it will pass through the device.

How reliable are the under sink hot water heaters?

Definitely, these little beasts are reliable ones, and you can trust them blindly for your hot water requirements.

How do I adjust the hot water volume under the sink?

First and foremost, you need to turn off the water to the sink.

Then, look for the water control valves under the sink.

The valve present on the right will adjust the hot water.

Turn the knob clockwise to increase the hot water volume, or counterclockwise to reduce the volume.

What type of amp break would be required?

In simple words, the type of amp break that you would be needing to a large extent depends upon the type of model that you’ve opted for, indeed.

For example, if the max amperage is less than 40, you’ll only need a 1 x 40-amp breaker.

Similarly, if the max amperage is 150, you’ll need 4 x 40-amp breakers.

In layman’s terms, it is your responsibility to ensure that the amp breaker in total can handle the max amperage of your unit.

Where is the best place to buy an under sink hot water heater?

Frankly speaking, the best place to buy an under sink water heater is or any other e-commerce website that you trust.

The good thing about the Amazon marketplace is that you can read the review of different models from a real person.

Wrapping Up the Under Sink Hot Water Heater

First and foremost, I would like to thank you for being with us till the end.

Secondly, I would like to bring to your notice that we’ve worked literally hard on this idiosyncratic superlative comprehensive buying guide.

And, in case, you’ve liked our effort then please do share this piece of information with the ones who are in need of it.

After all, sharing is caring, isn’t it?

Anyways, cutting long-story-short, let’s get back straight to the topic.

To be honest, the market is flooded with a wide range of under-sink water heater models.

So, we’ve tried to the best of our capabilities to provide you with the necessary information that will help you in making an informed buying decision for sure.

Lastly, if I’ve to pick one out of all the heaters that we’ve reviewed so far then it would be none other than the BOSCH Heater.

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