Top 7 Best under Sink Water Heater | In-depth Reviews & Buyer’s guide

Do you want to change your water heater and the expense holding you back? Then there is a great alternative which will give you warm water right where you want.

Under sink water heater!

This is an affordable solution for everyone who are struggling with the budget. They work pretty cool, same as a whole house water heater. The only difference is, they are meant to be mounted under the sink.

However, to save you from the hassle of going through hundreds of different models to choose one, we have come up with the top 7 best under sink water heater of the market. Check them out, hope you will find one for you real soon!

7 Best Under Sink Water Heather Reviews

When it comes to choosing the ideal under sink water heater, there are a lot of things that you should consider. From capacity to performance to durability, you have to ensure all of them. However lucky you, our team has done all the homework.

They have conducted all the tests and reached to the real users to know how these models actually work. And so far, these 7 model is doing incredible.

1. Eccotemp Electric Mini Tank Water Heater


  • Type: Under sink water heater.
  • Tank capacity: 2.5 Gallons.
  • Temperature: 50 to 140 degrees.
  • Heating capacity: 1440-watt.

The Eccotemp EM-2.5 Electric Gallon Mini is an incredible water heater where you can trust blindly. The brand Eccotemp is a well-reputed company serving the market for quite a long time now. Their design, quality and performance, everything is quite amazing. Users are pretty satisfied with their products. And if anything happens to the product, the customer service is there for instant help.

It is a small tank, 2.5 gallon but the heating performance you will get for this small heater that will amaze you. There are a bunch of features that are ideal but among them one feature that should be highlighted. And that is the temperature control of this heater. It comes with a build in temperature control which will allow you to increase or decrease the temperature from 50 to 140 degrees.

Besides being an ideal model for under sink, this very water heater is suitable for bathrooms as well. Thinking where you would mount that? The size of this heater is small and very lightweight as well, so you can even hang the heater in the wall. But if you have any better alternative than go for that.

And another satisfying feature of this heater is, it can give you warm water faster, it comes with a faster recovery rate. Moreover, this water heater comes with pressure relief valve as well which will lessen the pressure when needed. The valve increases the safety and also saves the heater as well.

With this water heater you will get 5-year warranty, so there should not be any hesitation for buying his heater since there is a long warranty.


  • Lightweight and compact.
  • Temperature adjustability.
  • Easy to mount anywhere.
  • Faster recovery rate.
  • 5-year warranty.


  • Operates little slowly.
  • Small tank capacity.

2. WaiWela WM-2.5 Mini Tank Water Heater.


  • Specifications
  • Tank capacity: 2.5 gallon.
  • Heating ability:  1320-watt.
  • Voltage: 110V.

This is another top-notch water heater brand that has been producing top-quality water heaters for pretty long time now. The WaiWela WM-2.5 Mini Tank Water Heater is doing absolutely fine job serving the user hot water. If you are looking for a small under sink heater, then this would be an excellent choice. The tank capacity is 2.5 gallon, that is not big but you are going to get warm water faster.

The design of this heater looks classy and construction is premium. Constructed with heavy duty material which gives it a long lasting life span. You don’t have to wait even couple of minutes to get warm water flowing from the sink. Since the capacity is low, it warms the water really quick. You can easily mount this heater anywhere you want, the size is compact and the weight is less, so floor, wall, or under, everywhere is suitable. Mounting it is super easy, requires five minutes maximum.

With this heater you get overheating protection. Means, the manufacturer didn’t think only about the water warming ability and durability, they have taken care of the safety as well. The overheating protection turns the machine off immediately after getting overheated preventing further damage to both the machine and things around it. This is a very user friendly water heater.

The power cord comes attached with the machine that makes very easier to operate it. Overall, the WaiWela WM-2.5 Mini Tank Water Heater is a good model who need small capacity tank. The price is not expensive and neither cheap, it is on fair range.


  • Very lightweight.
  • Compact size.
  • Easy to mount.
  • Highly durable.
  • 6-year warranty.
  • Overheating protection.


  • Small tank capacity.

3. Atmor Tankless Water Heater


  • Specifications
  • GPM capacity: 0.9 to 2.5 GPM.
  • Power setting: 3.
  • Voltage: 240V

Wouldn’t it be great if you get your hands on a water heater model which will save energy bill? The Atmor 13kw/240v, 2.25 GPM Tankless Water Heater is something like that. Using this water heater, you can save up to 30% energy. This heater gets activated only when it detects waterflow, otherwise it doesn’t get activated which is why it consumes less electricity than other heaters.

The design is compact and lightweight as well which allows you to mount it anywhere you want, floor, wall, or under the sink. You can use this water heater in two places obviously depending on the inlet water temperature, under the sink and in the shower. It can heat up 2.5 gallons water in every minute with 45 degree temperature raise. However, you have to make sure that you have selected the right unit depending on the incoming water temperature, flow rate and expected temperature.

This heater comes with a pressure relief device which should be installed in the cold connection heather inlet. The valve is for safety, whenever the pressure increases alarmingly, the vale will take care of it.  Let’s move on to the construction of this very heater. The manufacturer has used top-notch materials in the construction which makes it highly durable. This heater is heat resistant and got polymer reinforced construction. And one last thing, it comes with three power settings, high, medium and low.


  • Energy saving.
  • Compact size and lightweight.
  • Three power modes.
  • Easy to mount.
  • Can be used in bathroom as well.


  • No overheating protection, though it needs it badly.

4. Ariston GL2.5 Electric Mini-Tank Water Heater.


  • Type: Under sink heater.
  • Tank capacity: 4-gallon.
  • Power: 1500-watt.

Bosch is a well-known and highly reputed brand which is serving the market with good quality water heaters for very long.  And this Ariston GL2.5 is one of their creation. This is not actually mini and nether a large one, it has decent capacity. Comes with a 4-gallon water heater and can be mounted anywhere floor or wall. However, there are now some upgraded version as well of this GL2.5.

You can adjust temperature in this very water heater, there is an adjustment knob which can be reached only after removing the oval cover. It allows you to adjust the temperature between 65 to 145 degree Fahrenheit. The temperature adjuster is the front of the heater, so that is a clever thing done by the manufacturer, users will be able to access that easily. That being said, the improved version of this GL2.5 comes with new sensing probe which improves the temperature regulator.

Another satisfying thing about this very water heater is the installation. Installing it is as simple as plugging in anything. There is no hard wiring required, all you need to do is the plug the heater in. You will need 120-volt power outlet and 1500-watt power which are easily found in every household. This heater uses 12.5-amp power to heat up 4-gallon water.

This heater is highly durable since it is a glass lined tank with premium insulation. You will see a neon light when the heater is working, means it is heating the water. And the light will shut down automatically when the water is heated properly. Comes with a pressure valve which adds little safety. The manufacturer offers 1-year warranty on limited parts and 6-year for heat exchanger. So you should not worry at all about the quality.


  • Highly durable.
  • Easy to install.
  • Heats up water fast.
  • 1500-watt power.
  • 6-year warranty.


  • Needs heavy maintenance.

5. Ecosmart Electric Mini Tank Water Heater


  • Capacity: 6 gallons.
  • Power: 1440-watt.
  • Volt: 120V.

If you are looking for a highly durable and small under sink water heater, then you should go for the Ecosmart ECOMINI6 electric mini tank. Looks pretty classy and comes in 4 different sizes from 1 to 6 gallons. Now this very model is a big one, the tank capacity of this heater is 6 gallons.

Installation is a breeze, and can be mounted anywhere, thanks to the compact design and super lightweight. The simple and small design won’t be an eyesore to the interior of your kitchen wall, it will look good for sure.  After unboxing this all you have to do is, plug it to the closest electrical socket (120V) and you are done. And it will consume around 1440-watt power and draws total 12 amp, that is energy saving.

Features pressure relief valve that adds to the safety and obviously increases the life span of the heater. All in all, it is among the good options if you are looking for a long lasting under sink water heater. The manufacturer is highly reputed for their worthy product quality, so you should not stress much. Even the company offers 1-year limited parts warranty and 5-year warranty for leaks. So there is nothing to worry about, if anything goes wrong, the company is there to back you up.


  • Highly durable.
  • Very easy to install.
  • Lightweight and compact size.
  • 5-year warranty.


  • Overheating issue.

6. Ariston Electric under sink Mini-Tank Water Heater.


  • Tank capacity: 4 gallon.
  • Power: 1500 –watt.

Previously we have reviewed the backdated version of this Ariston GL4S mini tank water heater, now this GL4s version is the better version. There are a lot of improvement the manufacturer has made to this very heater. It can be mounted exactly where you want it to be, you can install it for the point of use easily. Doesn’t requires any hard messy wiring, this is a satisfying improvement. For installing all you have to do is plug in the wire to the closest power outlet.

Comes with a good looking sleek design and the size is compact as well. It weighs only 17 pounds, so mounting in the wall should not be an issue. The size will even allow you to set the heater under the counter as well. The tank capacity is 4 gallons, that is enough we think for a small family. Comes with a top-notch construction, this is heater is gas lined which means it is completely rust or corrode resistant and highly durable as well.

Unlike previous model, the manufacturer has improved the temperature adjustment knob as well for easy and faster access. With the temperature adjustment knob you will be able to adjust the temperature from 65 to 148-degree Fahrenheit. Using this you will be saving on electricity bills, it is energy efficient heater. Overall, a good one, the manufacturer offers 6-year heat exchanger warranty.


  • Rust and corrode resistant.
  • Highly durable heater.
  • Energy efficient.
  • Heats water faster.
  • Manufacturer offers 6-year warranty.


  • Small tank.

7. Thermoflow UT10 2.6-Gallons Electric Mini-Tank Water Heater.


  • Capacity: 2.6-gallons.
  • Heating ability: 1500W.
  • Temp range: 45-167 degree F.

And last but not the least, we have the Thermoflow UT10 2.6-Gallons Electric Mini-Tank Water Heater. Another incredible piece which is dominating its competitor pretty badly. One of the top-rated model of the market and best-selling as well. Good look, outstanding performance, and long lifespan, you will get everything from this very Thermoflow UT10 2.6-Gallons Electric Mini-Tank Water Heater.

If you need warm water immediately whenever you want, you might want to have a look at the Thermoflow UT10 2.6-Gallons Electric Mini-Tank Water Heater. Comes with amazing heating element and heats up water way too faster. One reason why this machine heats water faster is because small tank. The tank capacity is 2.5 gallons which is not suitable for a large family but excellent option for small families.

It got stainless steel construction that makes it highly durable and look classy as well. Moreover, this heater is energy efficient as well. Among all the features, the best one we think is the Thermoflow thermostat which enables the user to select the right temperature for them. So there will be no overheating issue. And temperature adjusting feature is also there, you can choose between 45 to 167-degree Fahrenheit.

Besides being very easy to use, this water heater is safe as well. Thanks to the Thermostop protection circuit. This circuit gives over heating protection by keeping the temperature at moderate level. If by any change the temperature increase alarmingly, the machine will shut down automatically.


  • Very easy to use.
  • Energy efficient.
  • Faster recovery rate.
  • Highly durable.
  • 2-year warranty.


  • Small capacity.
  • Size is big for under sink.

Things to Consider Before Buying the Best Under Sink Water Heater

To make sure that you are getting right water heater, there are some factors that needs to be consider prior to purchasing any model. We have demonstrated all the factors in detail, so that you can save your money by not investing on the wrong model. Check all the factors and choose a heater according to them.


There are two types of under sink water heater. Tankless and tank. Tankless heater means, the machine doesn’t come with tank and it doesn’t store water. You have to put in on the water outlet and when water will pass through that it will heat up the water. That being said, tankless water heaters are highly expensive but they are environment friendly and can give you instant warm water.

On the other hand, tank heater comes with a tank where it stores water and heats them slowly. You won’t get instant warm water in tank models but they are cheaper than the tankless model. So which one you would choose completely depends on you. If you want faster warm water, then go for tankless. And if you have budget issue, then go for the tank model.


If you have decided to go with a tank water heater then you need to think about the capacity of the tank. Do you have a big family? Then under sink water heater might not be a good option for you since the tank capacity is low. Under sink water heaters are best for small families, family of four people. However, there are different sized tanks, 2, 3, 4, 5, 6 gallons. Go for the higher capacity, that will benefit you in the long run.

Flow rate

The second most important thing you need to keep in mind before buying any water heater is the water flow rate. There are heaters that delivers low water flow and there are some which delivers high flow rate. Always go for the heater that comes with high water flow rate, that will keep the hot water access uninterrupted. There are some models on the market which offers 5 gallons per minute water. The higher the water flow, the satisfying the experience would be.

Energy rating

Another highly essential factor to consider prior to purchasing any water heater is the energy rating. The energy rating shows how good the machine can perform without consuming much energy. All the under sink water heater comes with good energy ratings, means they can warm large amount of water with a very small amount of energy. Go for a model that comes with higher energy rating, you will save money on electric bills.


When it comes down to under sink water heaters, size plays a major role. Try go for small water heaters so that you can easily mount that under the sink or counter top. Actually, which size you should pick depends on where actually you want to mount that heater. If you have a large under sink space, then it will be okay if you have chosen a large water heater. And if you have very tight space, then you have to go for the small ones. As simple as that.

Another thing to remember is, if you have plans to set the water heater in the wall. Then without any doubt you have to choose a heater that is highly lightweight.


Do not go for a water heater model that doesn’t offer warranty. The best option would be to go for the well-known brands. Doesn’t matter if they charge higher price but you will be getting the worthy product for sure.

Frequently Asked Questions

Q: Which one is the best under sink water heater?

– There are couple of models which are doing pretty great but the Eccotemp EM-2.5 Electric Gallon Mini water heater is suitable for everyone.

Q: Is tankless water heater worth the money?

– Definitely. Tankless water heaters are environment friendly and they can give you instant hot water.


Time to wrap up now. Hope you have got the best under water heater for you by now. And if there is anything else we can help you with, don’t hesitate to let us know!