The 5 Best Under Sink Water Heaters Review

Are you struggling to find the best under sink water heater?

If yes, read our reviews to find the 5 sought-after models available right now on the market.

Choosing the best of the best model is extremely important yet challenging as the market is positively flooded with many choices. What’s more, you have to consider many factors, including quality, performance, energy- and water-saving efficiency as well as the size.

Best Under Sink Water Heater

Such an overwhelming selection process could lead you to a hasty and eventually regretful purchase.

But, you don’t need to worry at all.

Hopefully, after reading our under sink water heater reviews, you can find the right one that fits your needs with ease.

Let’s get started.

Comparison Chart

Check the specs below before you go through our detailed reviews.

Product NamePrice On AmazonStyle/ Tank Capacity (gallons)Temperature (degree-F)Electrical Requirements (Amp/Volts)Dimensions (inch)Weight (pounds)
Bosch ES4 Tronic 3000 T  Check Latest PriceTank-type/465-14512A / 120 V13.75×13.75×13.5  17.4
Stiebel Eltron SHC 2.5 233219  Check Latest PriceTank-type/ 2.586-10511.3A / 120 V11×10.63×18.69  15.9
Ecosmart POU 3.5 Point of Use Check Latest PriceTank-less80-14029A / 120 V3 x 11 x 64
Camplux ME25 Check Latest PriceTank-type/2.550-14012A / 120 V11.75×17.25×10.38  20
Thermoflow UT10 Check Latest PriceTank-less45-16713A / 120 V18 x 12.2 x 11  15.7

How to Choose the Right Under Sink Water Heater

Before you spend your hard-earned money on any under counter water heater, you need to be sure that it offers what you require.

What following part is a rundown of the most important considerations to make when choosing this appliance. Be sure to consider them all carefully.


In general, two types of under counter water heaters are available— tank-type and tankless. Both have their advantages and drawbacks.

Tankless variation is the smallest option you’ll come across. It doesn’t include any storage tank. As soon as you open up the hot water tap, you’ll get what you need. This type is more efficient in terms of cost, as they don’t use much energy or water.

On the negatives, the tankless type is not a good choice if your hot water demand is high.

Tank-type water heaters come with a mini tank that usually holds 1.5 to 6 gallons of hot water. Most of the models are designed for wall-mount under your sink or directly onto the floor or shelf.

Although this variation has a storage tank, there is no need to set up additional pipes around your home. The downside is it takes up more space than tankless.

Calculate Your Hot Water Demand

To purchase an under sink or instant water heater that will be the right fit for your need, you should calculate your hot water needs per minute.

This appliance comes with a fixed GPM rate.

Moreover, if you plan to buy a tank-type heater, you must check how long the water stays hot in the heater.

Consider Where You Live

The incoming water temperature may vary depending on the region where you live. Making the right choice depending on your location could save you some money.

If you live in an area where the temperature is already warm, you don’t need to buy a powerful unit. A powerful model uses more energy, causing your electricity bill to rise.

Required Voltage

If you plan to install an under counter electric water heater, make sure how many volts it needs to run. Some models have a high electricity demand. Some runs at 120 volts, whereas some require 240-volt.

Energy rating

This is a crucial factor for all types of water heaters. The energy rating determines the capacity of the unit to perform well without high-energy consumption.

A mini-tank water heater with a high energy rating indicates that it can heat a large volume of water by consuming minimal energy.

Safety Features

Before making a purchase, check the safety features of the unit. Some of the safety features are auto shut-off function, overheat protection, freeze protection and more.

We suggest studying every function and feature of the unit so that you’re fully aware of its safety and function. If you’re not sure about any feature, contact customer care or a store representative who can sort out your query.


It is essential to understand how easy the installation of your selected model is. Although mini-tank and tankless models are easy to install, you must have good knowledge about the technique. For DIY installation, you should know what type of wires you might be requiring.

Now that you’ve learned the checklist for buying an under counter water heater, we hope you won’t face any difficulty while choosing the right one for your need.

Here are the Best Under Sink Water Heaters

To recommend the best of the best under counter water heater, we’ve invested a significant amount of time in selecting, researching and testing the units.

We’ve vigorously tested all these models to make our comparison as accurate as possible.

All the models on this comprehensive list are durable, functional, efficient and trendy to bring some style into your home, kitchen or the place where you install it.

Whether you’re looking for a water heater that will work for years or help improve your water- and energy-savings, we’ve got something for you.

So, without further ado, let’s check the models that make our list.

1. Bosch Under Sink Water Heater Electric, ES4 Tronic 3000 T

Bosch ES4 Tronic 3000 T

If you need a highly efficient and durable point-of-use mini-tank heater, you should consider the Bosch Tronic 3000 T ES4 instantly. It is a practical and effective solution to your hot water needs.

Bosch ES4 from Tronic 3000 T series is one of the industry’s best-selling mini-tank water heater, and for good reasons.

This 4-gallon unit provides hot water right where you need it. It can supply up to two sinks simultaneously. Plus, it comes with a fast recovery rate. That means you won’t need to wait a long time for hot water at your sink.

There is an external dial for easy control of the temperature from 65 to 145-degree F. You can choose between “min”, “ideal”, and “max”. Notably, the temperature-pressure relief valve enhances your safety.

Most importantly, impressive 98% thermal efficiency reduces energy usage and saves you money.

This electric water heater offers you a long service life. The premium glass-lined materials make the unit long-lasting. What’s more, it is insulated with a layer of thick CFC-free foam for thermal retention and added durability.

The versatile installation allows you to mount it on a shelf, floor or wall. You can plug it in to a 120-volt outlet for the sole water heating source. Thanks to its simple 120 VAc plug-in connection and 36 to 37-inch cord. In-line installation is also possible with any large hot water source.

Along with a compact design, Bosch ES4 fits easily under a sink, even in cabinet space. The unit’s sleek and attractive appearance will blend seamlessly with any existing décor if you plan to install it in a visible location.

Bosch clearly stands by their products with a six-year limited warranty for the inner tank. All other components and parts offer a two-year limited warranty against defects in workmanship or materials.


  • Designed for under-sink placement
  • Great for small spaces
  • Compact and lightweight
  • Fast recovery rate
  • Supreme energy efficiency (98%)
  • Easy to maintain
  • Versatile mounting option
  • UL listed for the US and UPC certified


  • The thermostat is too simple, so it may take some guesswork to figure out the exact temperature since the range is quite broad.
  • Water flow may reduce your water pressure if you use it for a shower or as a booster for your tankless water heater.

2. Stiebel Eltron SHC 2.5 233219 Mini-Tank Electric Water Heater

Stiebel Eltron SHC 2.5 233219

Stiebel Eltron is the world leader in the development of energy-saving and advanced water heating technology. Their engineering excellence and high-quality products fulfil the highest expectations of reliability and performance.

The Stiebel Eltron SHC 2.5 233219 mini-tank electric water heater is no exception.

This model is designed for the point-of-use application. It provides plenty of hot water for hand washing or small kitchen applications. You can also use it for low flow showers and laundry areas.

SHC 2.5 always delivers hot water when you need it. You can plumb with cold water to use it as a stand-alone unit. You can also use it as a supplement to an existing heater located far from the sink to minimize delays and energy use.

Conveniently, the thermostat dial is located on the top of the housing. So, you can easily adjust the temperature from 86 to 140-degree F. What’s more, this model allows you to maintain inner tank temperature above freezing point by its frost protection function.

The mini-tank design frees up precious space. The world-class insulation reduces standby losses, especially when compared with larger tank-type models. It saves you money by reducing energy needs.

This unit easily mounts right under the sink or sit on the floor. Thanks to its included bracket and flat back. No special hard-wiring is required for installation. Just plug the unit into a 120-volt standard outlet for easy installation and use. For added convenience, it comes with a T&P valve.

The lightweight and compact construction with a sleek design make this unit perfect for installing almost anywhere!

The glass-lined internal steel tank and Brass plumbing connections make the unit durable. Notably, Stiebel Eltron stands behind this model by offering a six-year warranty on the tank and a two-year warranty on all other components.


  • Designed for installation at the point of use
  • Freezing protection; perfect for colder climate
  • Convenient temperature adjustment
  • Lowest standby losses in the industry
  • Water- and energy saving
  • Lightweight and space-saving design
  • Wall-mounted with the included bracket
  • Decades-long life spans
  • Manufactured in Germany


  • Few users have complained about the rusting issue of the tank.

3. Ecosmart POU 3.5 Point of Use Electric Tankless Water Heater

Ecosmart POU35

EcoSmart POU 3.5 provides you with endless on-demand hot water for small water usage application. It fits in places like bars, bathroom, boats, RV, doctor’s offices where hot water demand is minimal.

It is easy to install, and the compact size allows for under the sink installation. The wall-mounted design frees up space on the floor to provide more storage space. Notably, it is 90% smaller than any tank-type heater.

The on-demand heating function cuts down on waiting for hot water. It provides hot water for one sink at 0.5 GPM in warmer climates. Of course, you can adjust the temperature from 80 to 140-degree F by using its Digital Temp Control Knob.

Advanced self-modulating technology allows the unit only to turn on to heat water only when you need it. Thus it cut down on heat losses, saving you a maximum of 50% in costs for water heating. (according to DOE)

Finally, Ecosmart POU 3.5 is backed by a one-year warranty on electronics, exchanger and element.


  • Quick and easy installation
  • Easy to follow the installation instruction
  • Very efficient
  • Fast and accurate
  • Fits almost anywhere
  • Well-made and durable


  • It is not recommended for areas where the inlet water temperature is lower than 57-degree F.

4. Camplux ME25 Mini Tank Electric Water Heater

Camplux ME25

Who says that you have to spend lots of cash to get a top-notch electric water heater?

Camplux ME25 is a brilliant pick if you’re on a tight budget.

Innovation, energy-saving and portability are the three vital elements of CAMPLUX products. The Camplux ME25 is no different.

This point-of-use mini-tank water heater is perfect for those enjoying the great outdoors. It is ideal for a patio kitchen station, basement wet bar, garage attic, boat, or RV.

It supplies up to 2.5 gallons of water per minute up to two sinks at a time. It fits under your sink or cabinet to provide plenty of hot water right where and when you need it.

There is a dial knob that lets you easily control the temperature range. Once set, the thermostat automatically controls the water temperature.

Conveniently, its red indicator light remains illuminated while the water is being heated. This appliance also provides protection against overheating. So, you can rest assured that it won’t cause a fire. Additionally, the CSA listed temperature-and-pressure relief valve of this model enhances your safety.

Importantly, this functional unit saves water by eliminating the long wait for hot water to reach the faucet. Thanks to its fast recovery rate. What’s more, it includes built-in insulation foam to reduce heat loss.

When it comes to durability, the high-quality built ensures its long service life. The glass-lined tank offers added durability.

Of course, the exterior of this unit is attractive and stylish. So, it’ll blend seamlessly with your existing décor when installed in any visible spot. The streamline elegant design cover will make your kitchen more pretty.


  • Highly efficient
  • Durable for long life
  • Minimal standby loss
  • Easy to use and maintain
  • Very friendly to install any small spaces
  • Easy to install
  • Freeze and overheat protection
  • IPX24 waterproof
  • UL approval safety
  • One-year warranty


  • Some users stated that the dimensions of the unit is a bit misleading. Due to the pipes, you have to add at least 4-inch to fit in a cabinet.

5. Thermoflow UT10 Electric Mini-Tank Water Heater

Thermoflow UT10

Are you living in colder regions or Northen USA? Need the best under counter water heater?

Thermoflow UT10 is great for colder regions. It offers you to select a temperature between 45 to 167-degree F. Its frost protection mode and energy-saving mode make the unit suitable for any season.

Thermoflow UT10 is designed for efficiency, durability and long life service. It suits for bathroom, kitchen, bar, hospital, school, office and RV.

UT10 is an actual Point- of- Use model that is specifically designed to fit  under the sink. The compact design fits in your cabinet or under the sink to provide hot water right where you need it.

Its maintenance-free stainless steel tank stores up to 2.6 Gallons of water to supply hot water quickly. The fast recovery rate eliminates long waits for hot water at your sink. EPS foaming technology ensures excellent heat retention.

UT10 is safe and reliable. It utilizes the latest German Thermostop technology for maximum energy-saving operation.

Its auto cut-off protection stops the unit from working if the water temperature reaches higher than the set temperature. Thus it prevents the unit from overheat and reduces the risk of damage.


  • Reliable and safe to use
  • suitable for any season
  • Quick hot water supply
  • Low standby loss power consumption
  • Overheat and automatic frost protection active
  • Premium built-quality
  • UL listed
  • Two-year warranty


  • The temperature dial knob is a bit weird to use.
  • DIY installation may take some plumbing know-how.


We’ve compiled an array of popular models which boast excellent user satisfaction ratings.

Hopefully, you had an excellent time reading through our 5 best under sink water heater collections. Most importantly, we believe that you’ve already selected a model from our comprehensive list that offers what you have been looking for.

So, are you ready to get hot water with a wink of an eye instead of waiting for long hours?

We’d like to hear from you on how the water heater you picked worked for you.

Other than that, feel free to reach out to us in case you have any question regarding the model we’ve reviewed here.

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