Best Electric Tankless Water Heater Reviews in 2018

Having the best electric tankless water heater is a blessing!

Why? You might ask.

I think you'll all agree when I say how tough it can be to get hot water when you need it.

You look forward to a shower and realize that all the hot water has been used up. Or you have to wait about thirty minutes for it to warm up again.​ 😯 😯

Not everyone has time to spare and that's what increases the need for an on demand electric water heater.​

Of course, finding the best tankless water heater might be tough.

But don't worry as we have created a whole list of electric tankless water heater reviews. All of them have been tested so you are assured about their performance.​

Best Electric Tankless Water Heaters: Comparison Table​


Yearly Energy Cost Saved

Average Gallons
Per Minute Heated

#1 Electric Tankless Water Heater - EcoSmart ECO 27

Our Top Choice


3-6 gallons

#2 Electric Tankless Water Heater - Stiebel Eltron Tempra 29


4-4.5 gallons

#3 Electric Tankless Water Heater - EcoSmart ECO 36


3.5-8 gallons

#4 Electric Tankless Water Heater - Stiebel Eltron Tempra 24+

Stiebel Eltron Tempra 24 Plus

Top Rated across the industry


5 gallons

#5 Electric Tankless Water Heater - EcoSmart ECO 11


2 gallons

#6 Electric Tankless Water Heater - Bosch WH27 Tronic


3.3 gallons

#7 Electric Tankless Water Heater - Ariston GL4S

Ariston GL4S

Space-Efficient Design


4 gallons

All of the electric tankless water heaters mentioned in the list are some of the best options you can go for.

Let's check go deeper and see what these best electric tankless water heaters can offer you.

  • The Best Tankless Water Heater for the Money
  • Our TOP Choice
#1 Electric Tankless Water Heater - EcoSmart ECO 27

The EcoSmart ECO 27 is perhaps the best electric water heater that is available today in the market. With its innovative technology and patented design, this tankless electric water heater helps you to save half the money you pay for hot water annually.

That is also why you'll find it at the top of our in-depth Best Tankless Water Heater Guide.​

The conventional heaters that you find in a majority of homes heat up the water and store it in big tanks, making it available throughout the household.

Electric tankless heaters, on the other hand, as the name suggests, don’t use tanks. With the help of a heating element, these heaters heat up the water when it travels through the pipes. This heating element is usually triggered by turning on an appliance that requires water.​


EcoSmart is well renowned for including self-modulating technology in their products. This technology lets the unit self-regulate the amount of energy required to heat the amount of water you want to use. This approach is not only beneficial for the environment but also helps you to save a significant sum of money.​

Weighing only 11 pounds, these units are quite compact and are wall mounted which in turn saves you space. Another greater thing about this heater is that it comes with a lifetime warranty!​

Smart Technology​

The Smart Technology included in this model operates at its best in areas where the temperature of the water is around 37 degrees. When working with this temperature of water, this model can heat up to 3 gallons of water in just a minute.

Moreover, with the ECO 27, you are in complete control of the power. This means that you can adjust the temperature according to your preference in 1-degree increments with the help of the digital display panel.​

Perhaps the most ideal places where you can use this electric tankless hot water heater is the southern and northern parts of USA because in the north, this heater can easily handle up to 3 gallons of water in a minute and it can also manage two showers running together without running out of hot water.

Meanwhile, in the south, where the water is warmer than usual, this heater can meet up the high demand of water for Jacuzzis and hot tubs.

In other words, this heater can heat up 6 gallons of water in a minute which basically equals to one sink and four showers all running at one time without the loss of heat.

Before you get this heater, meet sure that your electricity supply meets the electrical requirements of this heater which are 240 volts, 27kW and single phase.​

  • Save half of the annual water heating cost
  • Lightweight and compact
  • Can handle 3 gallons of water in a minute to 6 gallons
  • Installation and maintenance are hassle free
  • The heater reads the temperature where the tank is instead of reading it where the water is being directed
  • Top Rated across the industry
  • Energy and Cost Efficient Electric Model
Stiebel Eltron Tempra Plus 29 kW

Another one of our Best Tankless Water Heater Guide addition, this on demand electric water heater from Stiebel not only possesses an innovative design but also has excellent build quality.

This is a precise and an efficient heater, but it comes with a pretty hefty price tag. However, in the long run, this heater is the ideal choice for a large household that has three bathrooms and a greater demand for hot water.​

Automated Setting​

The Tempra 29 adjusts the internal setting automatically so that it uses the exact kilowatts of power required, in turn reducing the wastage of energy. Moreover, when the heater is used at more places simultaneously, it adjusts the flow of water so that you get hot water in frigid temperatures as well.

This heater prevents the fluctuations in water which occur when another source which requires hot water is turned on. This is done by lowering the temperature of water in real time. Due to how efficient it is, you won’t have to worry about rationing the use of hot water. Consequently, this heater is suitable for households with high-usage applications.​

Apart from being reliable and of high quality, the Tempra 29 comes with a three-year warranty on its parts. Moreover, it is well known for providing a problem-free performance for a long term.​

It might be a bit overboard for smaller applications; however, this is the ideal choice for a six person house which usually runs two or more showers at once, that too at a high flow! But compared to the EcoSmart ECO 27, the GPM (Gallons per minute) is low.​

  • Absolutely stunning performance; the heater provides constant supply regardless of the amount of appliances and fixtures running
  • Easy to install
  • Compact, therefore, doesn’t take up a lot of space
  • The automatic management system might not be up to par for some users
  • Simultaneous Delivery
  • Self-Modulating
Ecosmart ECO 36 36kw 240V Electric Tankless Water Heater

The EcoSmart ECO 36 can easily handle a single family household. When talking about its specifications, the ECO 36 can heat up to 8 gallons of water per minute however it is subjected to variation due to the external temperature.

It also offers more energy efficiency than the Stiebel Eltron Tempra 29. But it is the same as offered by the EcoSmart ECO 27.

Moreover, this tankless electric water heater weighs 17 pounds. While this isn’t really light, however, it is lighter than other models in the market, and you can still install it anywhere since this doesn’t really need a lot of space.

Simultaneous Delivery​

​Since this tankless water heater serves the whole house, it is designed in such a way that it provides hot water to multiple bathrooms and kitchens without any hassle or delay. This means that you can simultaneously use dishwashers and showers without installing these heaters at different spots.

Convenient Control​

The ECO 36 also provides you with ultimate control over the temperature of the hot water. You can make the water as hot as you want it to be.

This on demand electric water heater doesn’t have ranges for the temperature like a majority of heaters do. Instead, it deals with exact numbers which means that you have the power to control the temperature to a single degree.


The ECO 36 helps you to save around half of the money you pay for water heating annually. The self-modulating technology of the heater draws the exact amount of power you require to heat the water which basically translates to the fact that this heater draws power only when you need it. This in turn significantly cuts down your utility bill.​

  • Cuts down the energy cost to half the amount
  • Self-modulating feature that draws just the right amount of power
  • Allows you to control the temperature to a single degree
  • Gallons per minute fluctuates due to external temperatures and location
  • Slight delay in the flow of water as expected with a whole house unit
  • Doesn't require venting
  • Advanced Flow Technology
Stiebel Eltron Tempra Plus 24 kW, tankless electric water heater

The Tempra 24 from the German company Stiebel is a total game changer. This is one electric tankless heater that doesn’t require venting unlike the other models available.

The Tempra 24 has a sleek and compact design that you can get installed anywhere. As a result, this model helps you to save quite a lot of money on the initial upfront and installation costs along with helping you to cut down the energy cost by 15-20%.

For better energy efficiency, EcoSmart ECO 36 is a good option.

Advanced Flow Technology​

It is no secret that this model falls under the list of technologically advanced electric tankless heater thanks to its advanced flow control technology. Since Stiebel is renowned for meeting the requirements of their customers, the Tempra 24 has been redesigned completely from the inside.

The electronics have been replaced by heavy duty ones enabling the heater to provide you with a single flow sensor design.

The hinged cover of the Tempra provides you with easy access, and the advanced flow control allows you to control the power. This means you can control the temperature according to what you prefer and you will be supplied with a constant output regardless of the number of sources being used at one time.

As the name suggests, the automatic flow control technology adjusts the water flow while simultaneously maintaining the temperature of the water. As a result, this tankless electric water heater prevents the fluctuations in temperature.

Easy to Install​

Furthermore, the heater gives the customer convenience and is easy to install in place of a big tank heating system. Since the system doesn’t require any venting, you can save on piping and other installations as well.

Last, but not the least, the model comes with a three-year warranty.​

  • Cut down around 20% of energy cost
  • Since no venting is required, you get to save additional money
  • Compact and light model; can fit anywhere
  • Advanced technology ensures a constant supply of hot water
  • Installation is slightly tricky
  • Initially, the system takes more time to heat the water in colder regions
  • Energy Efficient
  • Self-Modulating
EcoSmart ECO 11 Electric Tankless Water Heater

As mentioned in the previous EcoSmart models, the ECO 11 also comes with self-modulating technology with which, the unit can itself regulate the amount of energy required to heat the exact amount of water you require.

As a result, you get to save money, and you don’t have such a negative impact on the environment.

Energy Efficient​

With the ECO 11, you will always have a ready supply of water. You will be able to save around 60% of what you spend on energy cost, which is more than the Stiebel Eltron Tempra 24.

Moreover, the unit comes with a lifetime warranty, ensuring a constant supply of hot water.

Weighing only 6.5 pounds, the unit is quite lightweight and can be placed anywhere around the house. Due to its compact size, the ECO 11 is the perfect choice for less spacious apartments.

The unit can heat around two gallons of water in a minute and is the most suitable to use in mild and warmer climates. Depending on the climate, you can either use it for single applications or multiple. The smart technology of the model allows it to adapt to different kinds of situations.

The bottom line is that this electric tankless hot water heater is an amazing and a pocket-friendly heater for those living in small apartments and can’t function without hot water.​

  • With this unit, you can save up to 60% on heating costs
  • ECO 11 comes with a lifetime warranty
  • Doesn’t take long to heat up the water
  • Electricity requirements are higher than those of other units
  • The performance of the unit differs in different climates
  • High-quality
  • Electric Flow Sensor
#6 Tankless Water Heater - Bosch WH27 Tronic

Bosch is a pioneer of great innovations and is an example of outstanding German engineering. The company is well known for its quality products, and the WH27 Tronic tankless heater is an evidence of this.

Compact Design

This tankless electric heater is not only a compact heater that you can install literally anywhere around the house but is also a powerful unit that is designed for both residential as well as commercial applications.​

The unit can easily provide a continuous supply of hot water to two major applications without any fluctuations or without running out of water.​

Electric Flow Sensor​

The unit is also fitted with an electronic flow sensor along with a modulating control unit. Both of these feature work to eliminate temperature fluctuation. As a result, regardless of how great the demand is, you get a constant temperature output.​

Energy Saving​

Perhaps the biggest plus point of this unit is the fact that it can cut the amount of money you spend on water heating by 97%! This is more than the EcoSmart ECO 11.​

The standby loss is also minimal, making this unit a great purchase. You can get around 3.3 gallons of hot water in a minute with this unit which is pretty great!​

Since this unit is quite lightweight and compact, storing it and moving it won’t be a problem. Other features of the unit include a filter screen on the inlet and scale prevention technology which is a relatively new feature in electric tankless heaters.​

This unit by Bosch also promises improved control as well as temperature stability.​

Moreover, with this unit, you also get a five-year warranty. The electrical requirements and the installation are pretty simple too. All in all, this unit is an excellent purchase.​

  • Thermal efficiency up to 97%
  • Endless hot water
  • Enhanced scale resistance
  • Compact thus can fit anywhere
  • Price
  • Space-Efficient Design
#7 Tankless Water Heater - Ariston GL4S

The Ariston GL4S is one of the greatest tankless electric heaters to date. Due to its compactness and the space-efficient design, the unit does not take up a lot of personal space. Moreover, it is also a durable unit.

The unit comes with an advanced point of use system with which you can get around four gallons of heated water in a minute. But the thermal efficiency isn’t on par with the Bosch WH27 Tronic.​


Due to the versatile design of the Ariston GL4S, you can use this tankless electric water heater with almost all faucets. For example, you can connect it directly to the shower and get hot water on demand. Similarly, you can connect it to other faucets or your kitchen sink and get hot water immediately.​

As a result, you are saved from unnecessary plumbing, and you get to save money since you don’t need to spend on plumbing. You also no longer require hardwiring thus saving additional money.​

The unit is also easy to install since all you have to do is to tap in the line supplying cold water and install the heater directly at the point of use. You can plug the unit in a standard 120V outlet directly.​

Therefore, it is safe to say that this unit provides maximum convenience. If you don’t want to wait for the water to heat up and you require additional volume, then you can simply install the heater in line with a much larger source of hot water.​


The unit comes with a new and improved thermostat featuring a unique sensing probe which is attached to the thermostat. This probe goes into the cavity of the heating element, and as a result, the unit is able to adjust the temperature at a much quicker rate. The heater is also able to maintain heat consistently.​

  • Inexpensive to run
  • Doesn’t take up much space
  • Can directly work on most faucets
  • Six year warranty
  • Tends to leak

Electric Tankless Water Heater Buying Guide

Determining the best whole house electric tankless water heater basically involves three factors:​

  • The price of the unit
  • The climate of the place where you live in
  • The amount of hot water you need

If you reside in a warmer place, then picking out a unit is slightly easier for you since a less amount of energy is needed to heat up the water. Similarly, if you buy a unit that can only heat up fewer gallons of water in a minute, then it won’t be a problem.

You will also be able to enjoy high flow rates that people living in colder places can’t. This is because, in colder regions, the unit has to work more which in turn lowers the total output capacity of the unit. If you reside in such an area that has a colder climate, then the recommended supply for you is 50%.​

The second thing you need to think about is the size of your household and the demand that you will be putting on the system at an average. Think about all these questions: will many showers be running in your house at one time? Will the dishwasher and sink be running while you shower? As the demand for water increases, the output capacity of the sink also increases so choose wisely.​

Before you go shopping for a unit, calculate the gallons of water you use per minute to get an idea of the maximum usage of the unit. Take into account all the people living with you and remember that there will be points where both you and the people living with you use the water at the same time.​

Next thing to consider is how conscious the people living in your home are when it comes to hot water. Also, think about whether you want to ration your usage of water or not.​

The last thing is your budget. Don’t forget to account the cost of installation as well when purchasing a unit. Every unit comes with a conversion and installation cost, and you should be aware of them when you calculate the budget.​

It is true that electric tankless heaters are comparatively cheaper than the gas ones; however, you will still need professional help for installation.​

Final thoughts​

The bottom line is that purchasing the best electric tankless heater is not only beneficial for you but is also good for the environment as it is comparatively cheaper and environment-friendly than the conventional tank heater.​

A tankless electric heater comes with numerous benefits such as a constant supply of hot water, greater amount of space, and reduced utility bills, which is why you need to purchase one for yourself soon!​

There is no doubt that after reading the tankless electric hot water heaters reviews mentioned above, you will be able to easily make an informed choice that you surely won’t regret!​

From the list, the best unit is the ECO 27 and provides excellent value for money. So, with the information present in this article, including the buyer’s guide, you will hopefully pick out a great unit.​