Best Under Sink Water Heater Reviews

Looking to enjoy the smooth flow of hot water on your premises? You need a water heater. These are appliances whose roles are to heat the water that flows through your home’s plumbing mechanism. They exist in various shapes and forms. Of these, the best under sink water heater stand out.

They are called under the skin because they are slim and compact enough to fit in the tiny spaces which exist beneath your sinks. With regards to this, they interfere less with the spaces which you might have in your possession. We have dedicated the entire length and breadth of this article to discuss them.

Top Picks : 5 Best Under Sink Water Heater

Top Under Sink Tankless Water Heater Brands

Some brands of water heaters stand out. The following are some of the most respected names of such appliances at the moment:



This is an Italian corporation which specializes in the manufacture of all kinds of heating systems and relevant products. Many people like its range of products due to its low consumption of electrical energy. They also perform well in the typical home owing to their compact size.



Bosch is a German multinational technology and engineering firm. It is headquartered in Gerlingen and makes great heating appliances and equipment. This brand is famed mostly because of its long-lasting products and outcomes. Once installed, it takes longer and yields more operations.



Atmor Industries Limited is a global leader in the manufacture of instant electric water heaters. Its products are prized mostly for their simplicity and energy efficiency. It stands apart from the others in that it cuts down the time required to give off the desired ends.



Looking for a compact tankless heater that can fit anywhere? Choose EcoSmart. This range of products is space-saving and features some compact designs. The compact size of this brand of equipment will let you fix them wherever you might have space to. You have them for your consideration in the home area.



From 1966 till now, Chronomite Laboratories Incorporated has engaged in the manufacture of instantaneous water heaters. These tackle a vast array of industrial, commercial, and institutional needs. Do you have a large-scale or commercial use in mind? Choose the Chronomite range of products.

Best Under Sink Tankless Water Heaters 2022

We devoted this segment to discussing the best appliances of this kind at the moment now. When compiling this list, we figured out the various benefits which each has to offer. Then again we factored the brand and the various uses to which they may be put.

#1: Ariston Andris 4 Gallon 6 Year 120-Volt Corded Point of Use Mini-Tank Electric Water Heater

Lack of the necessary wiring and electrical skills? Worry not. This heater has got you taken care of well. That is because it does not require that you possess too great expertise to work and engage.

Temperature Adjustment Knob

A brand new temperature adjustment knob exists on its front. You use this to raise or lower the desired temperatures. These span 65°F-161°F. The appliance hence lets you attain water at the temperature is desirable.

#2: Ecosmart POU 6 Point of Use Electric Tankless Water Heater, 6 KW

Is the space you have in mind too small? Get hold of this compact and space-saving heater. It is small enough to fit the smallest spaces available. Examples of these are recreational vehicles, wet bars, and bathroom sinks.

Controlled Heat Flow

With this appliance, you get to control the flow of heat. This simply means you get to vary the temperature of the water flow with the rate thereof. The end result of this arrangement is consistent temperature outputs.

Energy Efficiency

All factors considered, this appliance is truly energy efficient. A 72°F inlet temperature has the ability to heat 1 gallon a minute up to 105°F. Say no to higher utility bills and too long durations of time with these arrangements.

#3: Atmor AT-900-03 Single Sink 3kw/110V, 0.5 GPM Point-Of-Use Tankless Electric Water Heater and 0.5 GMP Sink Aerator

Have only one sink in your premises? This is the heater to think of using. Its compact size and the single unit allow for pairing with only one sink. To add to this, the heater also draws groundwater for processing.

0.5 GPM Aerator

Coming along with this heater is an aerator. Its discharge rate is an impressive 0.5 gallons per minute. The aerator mixes air with the water for appropriate aeration. Its existence brings in more for less.

Awesome Flow Rate

The heater manages an awesome flow rate of around 0.5 gallons per minute. Courtesy of this flow rate, the water reaches 45° within a short duration of time. It hence saves you some time and energy.

4: Bosch ES2.5-Point-Of-Use Electric Mini-Tank Water Heater, 2.5-Gallon

Want some convenience? Why not lay your hands on a heater that can mount on the floor or the wall like this one? Apart from ease of installation, it also gives those benefits which awesome heaters of their kind do.

Variable Sizes

Generally speaking, this heater is available in three main sizes. These sizes are also installed in different parts of the typical home. Examples are the floor and the wall hanging respectively. All these are for your convenience.

Glass Lining

The interior of this heater showcases some glass lining. The aim of this lining is to increase the overall lifespan of the appliance as a whole. It also makes it resilient to the common agents of tears and deterioration.

#5: Bosch Thermotechnology Ariston GL6+S Electric Mini-Tank Water Heater

Tired of having to wait for too long to draw your water? Get hold of this heater to put an end to that. Its faster operational speed cuts the time needed to wait that long. This results in time savings on your part.

Superior Insulation

Throughout its interior and exterior is some superior insulation. This is brought about by the glass lining on the tank. The insulation also brings about a longer lifespan as well as greater energy efficiency.

Compact Size

By all accounts, this appliance is compact in size. It is smaller in dimensions and weighs less on average. You will find it pretty easier to move around as the need may so dictate.

#6: Chronomite SR-20L/120 HTR SR Series Instant Low Flow Tankless Water Heater, small

Could it be that the space you have at your disposal is only horizontal in nature? If you answered in the affirmative, you want a heater that is similarly designed for installation in the horizontal direction like this one.

Compression Fittings

Some compression fittings exist in this heater. You use them to install and fix the equipment firmly in place. They are made of chrome and are mountable easily and on many surfaces.

Electric Knock-out

At the rear of the appliance is an electric knock-out. With this component, you will easily deliver the hot water necessary and at the temperature that is most convenient to you. This is not to mention being easily engaged.

#7: Stiebel Eltron 24 plus Tempra, Tankless Water Heater, White

Want some continuous supply of water on demand? This heater will give you much more than that. It also produces an unlimited supply of the same for your utmost peace of mind.

Sleek Design

All the various parts and components are packaged in some sleek design. In this way, the heater saves greatly on space requirements. It also calls for no venting at all on your part.

Electronic Switch

An electronic switch exists to let you easily activate the system. Other than the simplicity of operations, the switch also gives off silent operations. With this appliance in your hand, you are unlikely to interfere with others around you.

#8: WaiWela WM-1.0 Mini Tank Water Heater, 1.3-Gallon

Do you change locations every now and then? If you do, the heater you use has to be compact, portable and easy to install. Of all that is under review, none comes even close to this one, as you are about to note.

Adjustable Thermostat

The adjustable thermostat stands tall among its awesome features. The purpose of this is to maintain the consistency of the temperature of the water output. It does this without any contribution on your part.

Overheat Protection

Yet again, overheat protection exists to shield you from the adverse effects of overheating. It simply switches the system off in the event that it hits or tends to exceed a given limit.

#9: Bosch Thermotechnology Bosch Electric Mini-Tank Water Heater Tronic 3000 T 7-Gallon (ES8)

Of all the heaters we have under review, none is as great for small spaces s this one. This stems from its compact size and that ability to fit the most squeezed or cramped up of spaces available.

CFC-free Foam Insulation

Round and about the entire tank is some thick foam insulation that is CFC-free. Its existence maximizes the energy efficiency of the entire system. Further to that, it also cuts down the utility bills which are payable by you.

Pressure Relief Valve

For your own safety, the heater contains a pressure relief valve. When there is a buildup of pressure, this valve engages to release it to the atmosphere. In this way, it prevents any explosions from arising.

#10: EcoSmart ECO 11 Electric Tankless Water Heater, 13KW at 240 Volts with Patented Self Modulating Technology

If you are looking for a tank for regular use, you have to be wary of the energy costs. That can only mean finding one whose energy ratings are modest. This is the one we would ask that you try out.

Energy Efficiency

As noted, this equipment is energy efficient indeed. It has been noted to cut down energy consumption by a whopping 50%. In this way, it also cuts down your energy expenses substantially (60%). This makes you happy, definitely.

Wall-mounted Design

To fix this heater in place, you will utilize your walls as it comes in the wall-mounted design. It hence takes up limited space and inflicts the least interferences to the other occupants within your room.

#11: Thermoflow 12KW at 240V Tankless Water Heater Electric

Looking for a heater for your utility sinks and washbasins? None is as powerful as this one whit regards to that applicability. It can, in fact, impact a whole basin within the shortest time possible. Have it for your taking.

Alloy Bare Heating Element

Its heating element stands tall in that it is made of high-quality alloy material. Apart from generating high heat output, it also maintains the temperature levels long enough. It is hence a reliable companion.

2 Modes of Applications

With this heater, it is possible to employ two modes of applications. You may use it as a primary heater or as a booster heater. As you can see, it is a pretty good appliance to make use of due to higher returns.

#12: Camplux ME25 Mini Tank Electric Water Heater 2.5-Gallon, 1.5kW at 120 Volts

Wanting to go camping out? The heater you use has to be optimized for all matters outdoors? Without wasting too much of your time, this is the one to straight away go for. You will find it befitting your boats and recreational vehicles.

Thermostat Controls

Some thermostat controls do exist on this system. They basically play the role of maintaining the temperature of the water to desirable levels throughout. You also adjust your water courtesy of them.

High Limit Device

Other than producing sufficient levels of hot water, this device also protects you while in use. It does so by preventing the levels of heat from getting out of control. As soon as a preset level is attained, it switches off.

#13: Ecosmart ECO MINI 2.5 2.5-Gallon 120V Electric Mini-Tank Water Heater

Making use of a good heater need not necessarily mean stretching yourself too much. Indeed, a good one of this kind will let you do just but at the comfort of your own home. Why? Because it plugs into a standard 110V outlet.

Digital Output Temperature Display

In the course of utilizing it, you will get to track the progress of the ongoing heating. This you will do courtesy of the digital output temperature display unit. Chances of making any mistakes are kept to an absolute minimum hence.

99.8% Energy Efficiency

By all accounts, this system is 99.8% energy efficient. With regards to this, it saves much of your energy not to mention cutting down your operational expenses considerably.

#14: Rheem 240V Heating Chamber RTEX-13 Residential Tankless Water Heater

For your own convenience, you want a system that you have some form of control over. This one contains and is operable via some external controls. These let you alter the temperature in 1°F increments.

High Accuracy

Compared to much other equipment, this one is highly accurate indeed. Its accuracy is within the range of +/1 degrees. It complements external adjustable controls to make your use hassle-free.

Durable Copper Immersion

A durable copper immersion also forms part of this system. It adorns two heating elements that provide the boost needed to create the heat energy. Being durable, it costs less to maintain.

#15: ECOTOUCH Tankless Water Heater Electric, 1.5 GPM on Demand Hot Water Heater Digital Display Energy Efficient 5.5kW at 240V, Black

Are you in a commercial setup and want to churn out higher quantities of water at a time? You need a heater that is multipurpose in nature, has a higher volume and is easier to operate. None comes close to this.

Smart Self-adjustment Technology

Uniquely setting this heater apart is the smart self-adjustment technology. Not only does it minimize energy waste but also does it attain 65% energy saving. Say no to higher utility bills henceforth.

Touch Control Panel

Engaging the various controls of this appliance is not so difficult. That is because you make do with the touch control panels. They are simple and easy to get by when compared to the other manual operations.

Types Of Water Heaters

Best Under Sink Water Heater
Types of Water Heaters

There are five main kinds of water heaters. They are explained hereunder:

Conventional Storage Tank Water Heater

This is the one you are most familiar with. It contains a tank and a heating element. Generally, it is larger and takes up more space. This is the one that is standard in many homes. Its most serious downside is the fact that it takes up more space and consumes too much power.

Tankless Water Heater

As the name implies, this one lacks any tank. Instead, it heats water instantaneously. For this reason, it is also called an on-demand water heater. Whereas it has a higher acquisition cost, this kind of tank saves your maintenance and heating costs in the long run.

Heat Pump Water Heater

Also called a hybrid water heater, this is an appliance that may operate as a tankless or a conventional heater at the same time. Perhaps the most notable benefit of this tank is its comprehensive approach towards matters of water heating. You will not have to look elsewhere for your heating needs and applications with it in your hands.

Solar Powered Water Heater

You may well have already guessed. Solar-powered is so-called because it derives its heating energy from the sun rather than gas or electricity. If you reside in an area that experiences abundant levels of sunshine, this is the one to go for. Being solar-powered also makes it cheaper to operate and utilize.

Condensing Water Heater

Condensing water heaters use gas to generate the energy required to heat the water. When water is heated using gas, it flows and mixes uniformly, hence the term, ‘condensing water heater.’ You will find this kind of tank most relevant for commercial uses and applications.

Tankless vs Tank Water Heater Calculators

Best Under Sink Water Heater

To find out how the tankless and tank water heater systems fair with regards to energy efficiency, it is necessary to look into their energy savings and the expected energy savings over the lifetime of each piece of equipment.

Generally speaking, ordinary tank systems save 10-20% of energy which translates to around $500. The tankless systems, on the other hand, save a whopping 45-60% of energy or $1,800. The exact savings vary though with the source of energy. Those powered by gas tend to save less when compared to those powered by electricity.

With regards to matters of energy savings, it is quite clear that the tankless is the better of the two pieces of equipment. It is certainly in your best interest to prioritize it.

How To Buy Water Heaters

Finding the best under sink water heater is ordinarily an intriguing undertaking. To be on the safe side, you have to take care of a number of factors. The following are the top issues you have to consider while finding the right one:


How much water can that tank heat and discharge per unit time? The choice of the most suitable heater under this consideration depends largely on the volume of water you want per unit time. Choose one with a higher capacity if you want more water and vice versa.

Tankless vs. Tank Water Heaters

Though many, water heaters may be subdivided into two main kinds. These are the tankless and the tank respectively. You have to make up your mind with regards to the one you prefer from these two. Generally, choose the former if you have plenty of space in your premises. The latter comes in handy if you have little space and is intended also on cutting down your operational expenses.

Fuel type, Availability, and Costs

Operating these heaters cost money and require some fuel. Yet again, you want to take care of these as well. Choose one whose source of fuel you can easily access and bring in. Then again, you have to care for the costs of operating this equipment for an extended duration of time. In case you can find one that accepts many fuel sources, by all means, go for it.

Size vs Mounting Space

How much space do you have in your possession? It is necessary that you factor this too. A good tank ought not to demand that you set aside too much space. This will definitely disparage your own comfort and pose unnecessary nuisances in the course of use. As a general rule, the smaller and the more compact the appliance is, the better!

Energy efficiency/Voltage Type

Check out the energy efficiency and the voltage ratings of the appliance you are interested in. Obviously, you do not want to spend too much of your money to operate these systems. Good equipment on the basis of this consideration is one that consumes the least energy yet exudes the highest power output imaginable.

Costs vs. Financial Resource Endowment

Lastly, of course, you want to see to it that you do not spend too much to purchase the one you like. Carry out some assessment of your own financial resource endowment. Then pick one whose costs fall well within your own budget. Do not compromise your own quality and comfort as you go about this role.

Water Heater Maintenance Tips

Though heaters vary in scope, shape, and structure, they exhibit some universal characteristics. The following are the steps you will need to follow to maintain yours in the best shape and form, regardless of the brand.

Take note though of the unique traits which your own heater might possess. That way, it will be possible for you to vary your efforts appropriately.

Familiarize yourself with your own kind of heater

Heaters vary in types and functionality. As a first step, you want to familiarize yourself with your own heater. This way, you will know the steps to follow to care for and maintain yours.

Check for leaks

Now move on to check for leaks. These are perforations within the plumbing mechanisms that let out water. In most cases, they do arise at the joints.

Inspect the plumbing joints

As noted, the plumbing joints are more predisposed to the risks of leakages. That is why you want to pay specific attention to them. If you note some rust, that is a sure sign of leakage and subsequent need for repairs.

Pay some attention to the couplings and gas hoses

Even the couplings and gas hoses do get affected by the issue of leakages. This is especially the case for those heaters which derive their power from gas rather than electricity. While at it, pay some keen attention to the hoses.

Take care of the surrounding area as well

Even the area that adjoins the heaters matter. That is why you want to take care of them too. Never let any flammable material stay next to the area. The nearest object should be no closer than 3 feet.

Test the temperature and pressure (T&P) relief valves

These valves play the role of enhancing the safety of the entire plumbing system. It is hence very much in order to ascertain that they are in the best of conditions. In particular, they have to open and close properly.

Listen for any unusual sounds

Part of the care and maintenance entails listening for any sounds that are unusual. Usually, when the water leaks, it emits a sizzling sound. It hence follows that the existence of such a sound is a sure sign that there is a problem.

Flush out your tank

From time to time, you are required to dismantle the system and flush out the contents. Doing so shall eliminate all debris that may have accumulated with time. In this way, the system shall stay composed and in good working condition for longer.

Inspect the Anode Rod

Lastly, you also want to inspect the anode rod. In fact, you are advised to change it at least once every three years. If you note any corroded parts, take the earliest opportunity to replace that specific part.

NB: Kindly note that some maintenance tips may not apply to your specific appliance. That is why we reiterate a second time that it is important that you pay keen attention to your specific brand. You want to know, through the manufacturers’ manual, the specific approach which yours will have to go through.

Frequently Asked Questions (FAQs)

We now look at some of the questions that are frequently asked with regards to this subject matter. The aim of doing so is to see to it that you receive balanced views and approaches concerning this wonderful subject and equipment.

Are under sink tankless water heaters really efficient?

– YES, they are! Most of them are in fact near the 100% energy efficient mark. This is brought about by a combination of factors. Among these are the point-of-use water heating approach and the little space they take to operate.

How big of an under sink tankless water heater do I need?

– The exact size depends mostly depends on the space that is available at your disposal. Be sure that the one you choose is able to fit the limited space you have. Then again, it has to be compatible with the rest of the plumbing system and components.

Do you really save money with an under sink tankless water heater?

– YES, you do! And a lot of money for that matter. The main reason is that you only heat the water if and when you need to. Then again, you do not have to set aside too much of your space to install the product. Lastly, they require less care and maintenance as well.

Is an under sink tankless water heater really worth it?

– YES, it is! In fact, you are strongly advised to prioritize it over and above the one that contains the tank. With this system at your fingertips, you do not have to spend too much on your utility bills. Their only major downsides are the fact that they cost more to acquire initially.

What are the downsides, if any, of the under-sink tankless water heaters?

-Some of the most notable downsides are higher acquisition costs, low water handling capacities, and high gas consumption (for those that are gas-powered). These disadvantages notwithstanding, they are still worthy purchases for the modern home.


We have done much we can to familiarize ourselves with this wonderful piece of home equipment. We now leave it up to you to carry on from where we have left. This can certainly mean nothing else but striving to acquire one for yourself. The best under sink water heater we have reviewed above are your first points of contact.

To find the best one, read through each review a second or third time. While at it, compare each of them to your own expectations and circumstances of use. Then, narrow it down to that one that most likely mirrors your unique expectations and conditions of the home.

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