7 Best Under Sink Water Heater Review 2021 (Buyer Guide)

If you are looking for a new era water heater that will free you from waiting for enough hot water for a long time and prepare it quickly, go for an under sink water heater review.

 These stylish water heaters are compact in design and have multiple functions. It can be installed anywhere without the use of complicated cables. Unlike other water heaters, the installation process when setting up these stylish water heaters is hassle-free. These modern water heaters are ideal for residential and commercial applications and can hold up to 7 gallons of water. Most of these electric heaters require a 120-volt outlet, but some models have a 240-volt outlet. However, the power consumption depends on the model. The best thing about a sink water heater is that it is environmentally friendly, energy-efficient, and saves up to 50% on your monthly electricity bill. In other words, having a water heater under the sink is a good value for money.

Under-sink water heaters are a smart choice because:

  • They are usually near the water outlet and save a lot of water that is usually wasted when the main water heater is on.
  • They come with a tank or tankless for convenience.
  • Save on additional installation costs for long pipes, lines, or pumps.
  • Save up to $ 100 by reducing heating costs.
  • Compact, lightweight, and compact, it saves a lot of space.
  • It comes with a quick install procedure for easy installation.
  • They can be wall-mounted or placed on the floor.

That’s all, but the question remains which heater under the sink is right for you. Well, it happens that I have a detailed list for you to help you find your best under the sink water heater.

A quick comparison of the best Under-sink  Water Heater Review



Bosch Electric Mini-Tank Water Heater Tronic 3000


  • Made of high-quality material, long life.
  • 4-gallon mini point of use mini tank.
  • 98% thermal efficiency.
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top pick

Ecosmart ECO Mini Tank Water Heater


  • 99.8% energy efficiency.
  • Best small under sink water heater.
  • Lightweight and compact.
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Editor’s Choice

Stiebel Eltron Tankless Water Heater – Tempra 24 Plus


  • 7-year warranty.
  • Latest German flow control technology.
  • Water temperature for constant comfort.
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Instant Hot Water

EcoSmart ECO 11 Tankless Water Heater


  • Digital output temperature display.
  • 99.8% energy efficient.
  • Made in the USA.
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Camplux ME25 Mini Tank Water Heater


  • Save water and quick hot water supply.
  • highly efficient heating element.
  • Reduce heat loss.
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Rheem 240V Heating Chamber RTEX-13


  • On-demand, continuous hot water.
  • 99.8% Energy efficient.
  • Digital thermostatic control with LED display.
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Stiebel Eltron 233219 , 1300W Water Heater


  • Mini tank is made in Germany.
  • Stainless steel suction tube.
  • 6-year warranty.
Buy On Amazon

What is an Under Sink Water Heater?
Under sink water heaters are small and compact heaters, as the name suggests. You can fit them under your sink to heat the water within a few seconds. They are also known as point-of-use heaters. They provide hot water to the faucets directly.

Water can be heated in two ways: by connecting the mainline and by using a stove heater. For instant water heaters, they need to be connected to the main cold water line. When the user adjusts the temperature, it heats the water. Hot water enters when the faucet is attached. For storage heating, the water must fill the tank. You heat it and users can use it at any time. These heaters are very useful for instantaneous heating.

How Does an Under Sink Water Heater Work?

These heaters are very easy to use. It can be easily installed with the instruction manual. The user needs to install them under the sink (kitchen, bathroom, garage). They heat the main supply of water connected to it. Then they supply this hot water to the faucet.

With these heaters, you don’t have to wait long. You use less electricity and energy. These heaters require sockets to connect plugs for heating operations.

Why Did These Models Make Our List?

When you buy these water heaters, they will bring you many benefits. They include the latest technology and innovative features that are worth buying. Some of the great features are:

Instant Heating

Below the sink water heater, these are excellent alternatives to the manual heating method. You just need to install them under the sink and near the outlet. No need to use long circulation pipes or tanks. You are connected to the main source of hot water. They heat the water electrically in a few minutes.

Small space

These heaters are so small and lightweight that they take up less space. You can carry it wherever you go. The water heater under the sink has a compact and simple design. It has interesting features such as the latest thermostats and architecture. Therefore, it can be installed under the sink without worrying about its appearance or compatibility.

Energy efficiency

These heaters use a lot of energy and you need to consider that your electricity bill will increase significantly. But let me tell you that is not the case. They are almost 50% energy efficient. It works only when hot water is needed, saving electricity. When the water gets hot enough, it will turn off automatically.

Learn more about. How to Turn ON Water Heater | 8 Possible Reasons Electric Water Heater no Hot  Water |  7 Best Home Heating System


Bosch Electric Mini-Tank Water Heater Tronic 3000



Electric Mini-Tank Water Heater

Bosch Tronic 3000 T 4-Gallon

  • Flow rate-2.5GPM.
  • Size 2.5/4 gallons.
  • Voltage-12A/120 V.

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Bosch electric water heater that can heat up to 2.5 gallons with Point of Youth Technology. It fits perfectly under any size sink and provides instant hot water. With a thermal efficiency of 98%, it is a compact design that can be mounted on the floor or wall.

This is an excellent source of instant water heaters that will help you with one sink at a time. It can be used as the only water heater or as a buffer to be installed in combination with a tankless water heater with intermittent cold water. Equipped with a pressure/temperature limit valve to supply water as needed. Foam insulation without thick CFCs provides maximum energy efficiency, and glass-lined tanks add durability.

In addition to the self-supporting installation, it provides a fast recovery rate and eliminates the long waiting time for hot water in the sink. Comes with a bracket for easy mounting on the floor or wall. After installation, just turn on the hot water supply and the hot water will come out immediately.



  • Long-lasting quality
  • Excellent recovery rate
  • Easy to Install
  • Immediate hot water supply
  • Integrated into Bosch Thermo Technology
  • On-site mini-tank heating


  • The anode may require frequent inspection.
  • Overuse can cause water leaks on the floor.

Ecosmart ECO Mini Tank Water Heater



Ecosmart ECO Electric Mini-Tank Water Heater

Ecosmart MINI 2.5-Gallon

  • Flow rate-2.5GPM.
  • Size ECO MINI 2.5.
  • Weight-15.8 pounds.

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Water heaters are an integral part of our lives. Suitable for cold places. Today, traditional one-day water heaters are no longer preferred. They are expensive and not energy efficient. The mini-tank water heater is another new invention. They are also known as Point of Youth Water Heaters. There are two types of water heaters in the field.

Mini storage tank-2 gallons to 30 gallons capacity.

Tankless type-low water flows, but continuous supply, Mini tank water heaters are a great way to save space and keep your water warm. The mini water heater provides the extra hot water you need. EcoSmart is a popular brand in the water heater market. Eco mini 2.5 gallons offers many types of water heaters. EcoSmart Eco water heater is one of them. This model includes a mini tank with a capacity of 2.5 gallons. This device will be a great discovery for you.


  • Lightweight and low power consumption.
  • No need to install long and expensive circulation lines.
  • In summer, you can heat the water in two sinks at the same time.
  • No more manually waiting for water to heat.
  • It does not require a pump or storage tank, so it does not take up space.


  • Power buttons stop working after some time.
  • You can’t install it without the help of an expert.

Stiebel Eltron Tankless Water Heater – Tempra 24 Plus




Stiebel Eltron Tankless Water Heater – Tempra 24 Plus

On-Demand Hot Water, Eco, White, 20.2

  • Flow rate-0.50 GPM.
  • Heating capacity-24kW.
  • Weight-1 pounds.

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  • Tempra tankless electric water heaters need to be the right size and you need to refer to the size guide to determine the right model
  • This Tempra Plus model features advanced German-patented flow control that automatically reduces drainage to maintain temperature when the demand temporarily exceeds capacity.
  • Homes with two separate dedicated 50ADP switches and two separate leads of 8-gauge copper on the Tempra 24 Plus itself require a minimum total of 150A of service.
  • It requires a 240 or 208-volt power supply and has a maximum output of 24,000 watts at 240 volts or 18,000 watts at 208 volts.
  • Tempura Instant Water Heater provides infinite hot water at constant and constant temperatures of 20-60 ° C that can be set on the front digital display
  • The flow rate obtained from this boiler or another tankless boiler depends on the performance of the device and the temperature difference between the inflowing cold water and the inflowing hot water.
    With 99% efficiency, it usually saves 15-20% compared to electric water heaters
  • It should be installed vertically with the faucet facing down and using removable fittings such as braided flexible connectors to allow regular filter cleaning and cleaning. If hard water is present, a scale filter is recommended
  • Professional installation is recommended


  • Does not produce any noise during usage.
  • Digital display of temperature and preset memory button.
  • No ventilation or space required to store hot water.
  • If the need is greater than the sealing capacity, reduce the flow rate.
  • The latest German technology helps control the flow of hot water.
  • A small heater that consumes very little energy because of the auto modulation technique


  • May cause fire or sparks
  • Not enough hot water


EcoSmart ECO 11 Tankless Water Heater




EcoSmart Electric Tankless Water Heater

EcoSmart ECO11 240V 11 kW

  • Flow rate-2.6GPM.
  • Heating capacity-13 kW.
  • Weight-6.5 lbs.

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The EcoSmart ECO 8 is a tankless 8 kW instant water heater ideal for heating water in bathrooms, small sinks, office breaks, and other field or low flow applications.

Depending on the water temperature at the inlet, it can be supplied in the range of 0.8 to 1.9 gallons per minute. See our size guide for information on how to choose the best solution for your hot water needs. With EcoSmart, you can reduce wasted water and energy by allowing you to expect unlimited hot water and use it when you need it.

Infinite Hot Water-If the correct dimensions are met, the tankless electric water heater will provide infinite hot water as needed. Instead of storing hot water like a traditional water heater, it heats the water as it passes through the device.

Save money, save space, save energy

Save Space-While traditional tank heaters occupy a lot of space, EcoSmart’s stylish wall design creates space for more storage space and is 90% smaller than a tank.

Energy Saving-EcoSmart features state-of-the-art self-modulation technology that uses only the amount of energy needed to heat water when needed.

Time Savings-On-site installation and demand-controlled heating reduce the amount of time you have to wait for hot water.




  • Space-saving design.
  • Excellent energy efficiency.
  • Self-modulation technology
  • Continuous heating mechanism.
  • It can provide hot water to two showers at the same time.
  • Heat up to 2 gallons of water per minute.


  • May develop leak overtime
  • It does not store water


Camplux ME25 Mini Tank Electric Water Heater




Camplux Mini Tank Electric Water Heater

Camplux ME25 2.5-Gallon with Cord Plug

  • Flow rate-2.5GPM.
  • Heating capacity-1.4KW.
  • Weight-17.16 lbs.

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The Camplux ME25 mini-tank water heater stores up to 2.5 gallons of water and supplies hot water under the sink or basin where it is needed. Great for underground wet bars, patio kitchens, garages, attics, and even RVs and boats. Hot water is available immediately.

Save water by stopping waiting for hot water to reach the faucet and reducing heat loss.

Easy installation. Just touch the waterline and attach the heater to the sink. No need for expensive circulation lines or pumps.

The glass-enclosed tank provides excellent insulation and long life, and the quick recovery of the heater avoids long waiting times for hot water.

The temperature range can be easily controlled with an external dial, and the pressure and temperature relief valves listed in the CSA improve safety.

A stylized and eye-catching exterior design that blends seamlessly with existing decorations when placed in a visible location. This heater is perfect for any room.

Water heater dimensions: 14.5 “x 11.75” x 10.38 “; Weight: Approximately 20 lbs.




  • Easy to install plugin style.
  • Available for wall and floor mounting.
  • Fast recovery rate.
  • Extended thermostat function.
  • Frost prevention technology.
  • Temperature control mechanism


  • Specialized installation assistance is required.
  • Only one shower at a time provides hot water.



Rheem 240V Heating Chamber RTEX-13



pick #6

Rheem Residential Tankless Water Heater

Rheem 240V Heating Chamber RTEX-13

  • Flow rate-2.68 GPM.
  • Heating capacity-1.4KW.
  • Weight-17.16 lbs.

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Some Features

Providing hot water for multiple devices:

A continuous on-demand water heater with a flow rate of 4.8 gallons per minute is a great feature for any water heater, and everything is available in the Rheem Instant Water Heater. Compared to other large-capacity generators, this range is not very high, but for small studio apartments, it is enough to run the faucet and shower at the same time.

Reduce the cost of hot water supply:

Like other tankless, Rheem uses energy every time you turn on the water heater. In addition, it is 99.8% energy efficient, the best in the business, and features a 1.5 GPM water-saving showerhead. Overall, you can save up to 60% on energy costs compared to traditional water heaters.

Free up valuable storage space.

People living in cities like New York can easily understand how valuable space is. This powerful and small heater occupies 4 x 9 x 13 inches of space under the bathroom or sink and can be easily mounted on the wall.

Allows accurate temperature control:

Excessive heat or excessive heat can affect comfort when taking a shower or doing other laundry tasks. See Companies like Rheem successfully address this issue and set up an externally adjustable digital thermostat control with a +/- 1-degree precision LED display that can accurately set the desired temperature. ..

Easy installation:

Includes 1/2 NPT adapter and 1/2 inch side compressed water connection for easy installation. It also supports 240 volts, 54 amp lines, allowing you to quickly connect a single 60 amp circuit with just a 3-foot 6 AWG cable.

Easy replacement of internal parts:

The internal components of this Rheem RTEX-13 consist of a sturdy copper dip with a brass plate for added durability. Durable copper immersion heaters can also be repaired on-site.

Extended warranty:

If you purchase a Rheem instant water heater, you will receive a 5-year warranty on the heating room and a 1-year warranty on other parts.


  • Small size, lightweight, easy to install.
  • Space-saving.
  • Great for small families.
  • Copper and brass components.
  • Has excellent energy efficiency.
  • Adjustable digital thermostat control


  • It provides a hot water flow of only 4 GPM with a temperature rise of 22 ° F.


Things to consider before buying a mini-tank water heater

Most homeowners these days are looking to buy equipment that not only has great features but also requires minimal installation space. Water heaters, for example, have significantly improved appearance, design, technology, and even installation technology. This is one of the main reasons why mini-tank water heaters have long been popular in many homes due to their quick heating solution and energy efficiency. Unlike regular water heaters, it does not require heavy cables, so installation is not complicated.

However, there are some factors that buyers need to consider when choosing a mini-tank water heater. Let’s see:

Check fuel source-

You’re shaking an old stove to bring in another fuel source, so you need to check how useful it is. To do this, you can contact a contractor who can help you analyze the cost of drawing a new connection for a mini-tank water heater. If you find that you can save a significant amount of money each month.

Check capacity-

 It’s a mini water heater, but you need to check its capacity to see how small the radiator is to provide enough hot water for your home. You also need to check how hot the water in the heater is and how high the flow rate is. Many homeowners tend to check the capacity of older models to help determine newer models. But that’s not wise. Keep everything fresh and forget about the ones you used in the past.

Check the energy classification-

 This is a very important consideration for all types of water heaters. It is important to monitor the energy class. This is to determine the functionality of the device without consuming large amounts of energy. Specifically, it shows that a highly rated mini-tank water heater can heat a large amount of water with a minimum of energy.

Understand safety features

 Before buying a water heater, it is essential to consider its safety. The best way to check this is to see if the heater has an automatic shutdown feature in the event of a malfunction. Therefore, it is always good to study all the properties of a stove in order to fully recognize how it works and therefore its safety. If you have any questions about the features, please contact customer service or a sales representative who can resolve the issue.

Understand how easy it is to install.

It is not necessary to install a mini-tank water heater, but you need to have a good understanding of the installation technique. Even if you have a user manual, you still need to talk to an electrician who can set the heating. If you do this yourself, you need to know exactly where to put the heater under the sink and what kind of cord you might need.

Once you get used to the mini-tank water heater purchase checklist, you no longer have to struggle to choose the right one for your home.

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