Best Electric Tankless Water Heater 2021

Did you know that an average US household uses up to $600 for water heating alone? While this is the blunt truth, an Best electric tankless water heater can help you save up to $100.

As the most affordable options, these heaters will give you constant hot water without the limitations of a tank. Whether you live in a bustling household or an apartment, there are several heaters you can choose from.

Continue reading to find the right one for you.

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The Best Electric Tankless Water Heater On The Market 2021

1. Rheem 240V Heater RTEX-13 Residential Tankless Water Heater

Rheem RTE-13 is not only one of the most popular units but functional as well. Featuring an external adjustable thermostatic control and LED display it’s one heater that you can rely on.

With its power control self-modulating and its two elements based on durable copper immersion, you don’t have to worry about uninstalling it in case something goes wrong.

Its simple design and small body also allow you to install it in your apartment if you have a small space.  As one of the most efficient heaters, it will provide you with endless hot water on demand for a single point of use and multiple applications.

Coming with everything that you need you can install and start using it within minutes. Weighing only 8.5 pounds it’s and measuring 4 x 9 x 13 inches, it’s best suited for apartments and small homes.

What sets it apart from other heaters is its energy efficacy. You can also use it to power two showers with 1.5 GPM low flow showerheads.


  • Its maximum flow rate of 4GPM is quite a lot for its price
  • Small and compact you can install it in tight compact places including a small cupboard and above the sink
  • Since it’s quite affordable the energy savings will pay for it quite quickly
  • Features a digital thermostat display


  • If you have multiple showers it may not be enough
  • It’s not optimal for the coldest temperatures.

2. Stiebel Eltron Electric Tankless Heater – Tempra 36 Plus

Manufactured in Germany, Stiebel Eltron ElectricTankless Heater Tempra 36 Plus has outstanding built quality and innovative design that makes it extremely efficient and worth the price in the long run.

If you have a large a house and huge family, it’s the best unit for you. With its smart design, it will automatically adjust its settings to use the exact amount of power so as to avoid wasting energy.

It will also adjust the water flow during high use to ensure that you get the right amount of hot water even in frigid temperatures.

Unlike other heaters, it has a self-modulation feature that will automatically detect the temperature of the water and apply the required energy to heat it up. This will significantly help in saving energy.

Also, when a shower is running and someone opens a tap its constant temperature output will prevent the temperature from dipping.

With its smart internal circuit system, you won’t have to spend a lot of money on electricity bills.


  • It’s fitted with an overheat protection feature
  • Self-attainable and straight forward installation process
  • It comes with a 3-year limited warranty for both commercial and domestic usage
  • It works well with both 208 and 240 volts electrical wiring


  • It’s a little bit expensive as compared to others
  • It does not work with a 200 amps

3. EcoSmart ECO 27 Tankless Water Heater, 27 KW at 112.5 Amps

If you are looking for one of the most popular electric tankless water heaters, EcoSmart ECO 27 is the right option. As a very efficient water heater, it has a total wattage unit of 27 kW which is separated into three heating chambers.

Since the heating chambers allow it to only use the amount of energy needed, you’ll save your water heating cost by up to 50%. Just like other heaters, its GPM flow rate is determined by the temperature rise of the incoming water.

Another impressive thing about it is its compact design. As compared to other modern-day heaters, it will help you save a lot of space with its design.

This means you can easily install it in your bathroom or even the kitchen. Its attractive and compact design also adds a natural gloss to your room and makes it quite attractive.

With features such as the self-modulation option, you’ll instantly get hot water while also saving on electricity consumption.

When it comes to power consumption, it operates at 112.5 AMP. It also has three double poles to provide you with the best results.


  • It’s fitted with a space-saving technology
  • It helps you save up to 50% of energy cost
  • It has a self-regulation mechanism to reduce costs
  • Its 98% energy efficient


  • Its flow of heating may be slow at times
  • Choosing the right size for your needs might be difficult

4. Stiebel Eltron Tempra Plus 24

As one of the industry leaders, Stiebel Eltron Tempra Plus 24 is a unique electric water heater that you can rely on. Although it comes at a slightly higher cost, it’s a good heater if you are looking for guaranteed quality.

Featuring a sleek German design and top-notch engineering, this electric tankless heater will meet all your domestic needs and costs. Suitable for a small home, it has a GPM of 4.0 which is good for instant water heating.

With its convenient design and digital controls, you can comfortably mount it on the wall, behind the furnace, or even within the utility closet.

It also has an updated temperature display with memory buttons to make it easy to use. However, its ability to provide constant hot water depends on the temperature of your groundwater.

If the temperature of your groundwater is 52 °F, it will provide you with a 3.1 GPM hot water flow rate.


  • It allows you to limit the temperature to 109 °F
  • It’s fitted with a microprocessor that regulates the inlet and the outgoing water temperatures
  • It has a digital design that makes it highly efficient
  • Its advanced flow control feature slightly lowers the water flow when the demand goes up


  • Since its heavy, installing is a bit costly
  • As compared to other heaters, it has a lower GPM

5. Bosch Mini-Tank Electric Water Heater Tronic 3000 T 7-Gallon

Coming with a 7-gallon capacity, Bosch Mini-Tank Electric Water Heater Tronic is perhaps one of the best electric tankless heaters out there. Simple and convenient, this water heater can comfortably fit under your sink to provide water right where you need it.

Regardless of how you install it, you can rest assured you’ll get the right amount of amount. If you install it vertically you’ll get 7 gallons of water supply.

However, if you install it horizontally you’ll only get 5.1 gallons of water. To provide you with reliable on-demand water, you need to hardwire it.

Its additional features include a temperature range of 65-145°F, a heating capacity of 1440 watts, and an operating pressure of 150 PSI.

Very easy to mount, you can safely install it on the shelf, floor, or wall. It also has a bracket for vertical mounting. To install it directly at the tank you simply need to tap into the cold water.


  • It has a 98% thermal efficiency
  • Made of premium glass-lined material
  • Comes with a 7-gallon water capacity to provide you with all the water you need
  • Features a sleek and compact design


  • It may come with a hot defective element
  • It has a confusing warranty

6. Eemax EEM24018 Electric Tankless Water Heater, Blue

Eemax EEM24018 tankless water heater is a good looking metal option water heater. Although it may seem a little daring with its shiny blue exterior, it will suddenly improve your room.

Having a GPM of 3.5, it’s right in the middle of all the water heaters. It’s, therefore, suited for a home where the kids are no longer there.  It will help cater to anyone who visits so often.

While it doesn’t have a storage tank, it can supply you with nonstop hot water throughout the day. Compact and small in size you can set it where you need it.

The best part is that you can only activate it when you need it. This allows you to save a lot on energy costs. As compared to other heaters, you can use it to save up to $100 per year.

Stylish, strong, and water-resistant, it has a digital control system to help you increase or lower the temperature.

With its Copper Emerson heating elements and brass on top, you can rest assured that its study and durable. You can also comfortably mount it on the wall.


  • It has a sleek and fancy blue exterior to suit any room
  • Although it does not have a lot of GPM it has enough for your heating needs
  • It comes with extra accessories to make repair and maintenance work easy.
  • It can save you space, water, and energy


  • It comes with a short warranty
  • To set it up with a pipe you may need to invest additional money

7. EcoSmart ECO 11 Tankless Water Heater Electric

Coming in different sizes, EcoSmart ECO 11 Electric Tankless Water Heater is a special heater that provided different GPMs. If you need an EcoSmart brand that suits your needs it’s the right product for you.

Its unlimited warranty means the company believes in their product. With this in mind, you can buy it in peace knowing that you are getting a good product.

In case of anything, they can fix or replace any part at no additional cost.  Apart from reducing your energy cost, it helps you save money in other ways.

With this electric water heater, you’ll never run out of hot water.  Once you choose the right size, you’ll get endless on-demand hot water. Unlike the traditional water heaters, it heats water as it passes through.

Small in size, it won’t take a lot of your space. By mounting on the wall, you’ll save your floor space for other things. To top it all it’s the smallest


  • It fits neatly into any part of your home hence help you save space
  • It’s among the only options with a lifetime warranty
  • It has several positive reviews. This means customers love it
  • Provides constant flow of hot water


  • Its low GPM is only suitable for small homes
  • You may have to remove and clean the elements after every 4 months

8. Rheem RTEX-18 18kW 240V Electric Tankless Water Heater

As a pro classic and energy-efficient electric heater, Rheem HEERTEX-18 Electric Tankless Water Heater is capable of providing you with endless hot water for use in your home, showers, and sinks.

You may also use it in other additional applications. Fitted with a brass heat exchanger and rugged copper body, it can withstand all the harsh conditions.

Coming with a simple installation process, it will ensure compactness, longevity, and usability. Featuring a space-saving design, you can install it in any part of your house.

Whether you are a camper or you have a travel trailer, this is the right electric tankless heater for you. Its thermostatic control will also ensure you enjoy an unlimited amount of hot water.

On average, it will provide you with up to 5.0 GPM of water. This makes it suitable for 2 bathrooms in hot weather and 1 bathroom during cold weather. It’s, therefore, the perfect water heater for your home


  • Since it heats water when you demand it, it’s highly efficient
  • It has an outstanding maximum flow rate per minute
  • Use its on-unit control feature to adjust the temperature
  • Stylish and easy to install


  • Insufficient warranty, poor quality parts, and short life of the heater
  • Consumes a lot of energy when fully operating

9. Stiebel Eltron Tempra Plus 36 kW, tankless electric water heater

Powered by 150Amps, Stiebel Eltron Tempra Plus is one of the leading water heaters out there. This is especially true if you want to migrate from the traditional heating system.

As one of the few options that stand out, this heater will help you save up to 20% of your electric bill.

It also has a setup function that makes it easy to install and operate. Requiring an electric service of up to 300A, it makes the most of the energy supplied to provide hot water when you need it.

With its internal sensors, it can measure any small changes in heat levels to ensure you receive hot water whenever you need it.

Regardless of your water needs and the size of your household, it’s an excellent choice that will satisfy all your hot water demands.

Whether you live alone or share a one-bathroom apartment, this heater will never disappoint you.


  • Features dual stainless steel built to make it strong and durable
  • Suits a variety of applications and uses
  • Its eco-friendly and energy star certified
  • It’s simple and easy to install hence you can install it alone


  • It doesn’t work well in frigid climates
  • As compared to others its performance metrics lag behind

10. Stiebel Eltron electric 224199 240V, 1 Phase, 50/60 Hz, 24 kW Tempra 24

Stiebel Eltron electric 224199 240V water heater combines German engineering and technology to provide you with the best heaters. Designed to replace conventional heaters, this heater will produce an endless flow of hot water.

If you have a large family with two or three bathrooms, it’s one of the best options for you. Having the capability of producing 2.7 gallons of water per minute, you can always adjust it to meet your demands

To prevent scalding, you can set the temperature from 86°F – 140°F. As a 99% efficient water heater, it will help you save up to 20% on energy.

Small and compact, it measures 1.7″ x 20.1″ x 9.6″. This means you can install it anywhere in your home. The best part is that it does not produce any noise while working.

More so, it comes with a 3 years part replacement and a 7-year warranty against any leakages. In case of anything, you just need to contact the manufacturers and you’ll be sorted out within no time.


  • It produces up to 2.7 gallons of water per minute
  • Its input temperature is as low as 42°F
  • As compared to conventional heaters it uses 20% less energy
  • It’s small and compact hence can fit any space


  • Installing can be a bit challenging
  • According to users, it does not provide the whole house with hot water

Best Electric Tankless Water Heater Buying Guide

Determine the Flow Rate You Need

As compared to traditional water heaters, electric tankless heaters don’t offer an unlimited flow rate. Instead, they provide a specific output. If your demand is more than this you won’t receive any hot water.

To determine the flow rate, identify the number of devices you have, and then use it to calculate the flow rate you need. The best electric tankless water heater should exceed this.

Check the Efficiency of the Heater

The best electric tankless water heater should use less electricity to heat water. The more water you require the less efficient your unit will be. So if you have a huge requirement make sure you have at least 90% efficiency.

Installation Process

While electric tankless water heaters are less expensive, some homes may not have that the electrical requirements needed. Installing one will, therefore, require a lot of money which will increase the installation cost.

Design of the Heater

Most electric tankless water heaters are simple. Although they look quite appealing, they may not have all the features you need. So while looking for one, choose a design that’s easy to diagnose and repair. It should also be small and compact so as to fit anywhere.


Apart from the functionality of the electric tankless water heater, it’s very important to choose a convenient and safe unit. For example, the best heaters come with select protection systems such as temperature lock, freeze protection, self-modulating technology among others.

LCD Control Panel

The right tankless heater should be fitted with an LCD control panel for easy control of all its settings. With this panel, you can adjust the program and temperature for an efficient heating system. Such a heater will definitely suit all your heating needs.

Durability and Construction

If you want your heater to serve you for a long time, consider its durability. An example of good construction is the one built of stainless steel. Apart from providing you with long service, it heats relatively faster. Plus, it maintains their hotness hence you don’t need to overheat.

Know About the Warranty

The best heater should come with a warranty. Contrary to what many people know not all heaters come with a warranty.  Instead of going for a short warranty choose one with a long warranty. A good warranty means the manufacturers have done everything to ensure it’s the best.

Frequently Asked Questions (FAQ)

What’s an electric tankless water heater?

Also known as instantaneous or demand-type water heaters, electric tankless water heaters are the type of heaters that provide hot water on demand. Unlike others, they provide you with hot water when you need it.

How does a tankless water heater work?

When you open the faucet, the flow of water will activate the heater and turn it on. The electrical burner will then heat the water as it passes through the unit. When you shut off the water supply, the unit will be powered off automatically.

Since the water is instantly heated the time required to get hot water depends on the distance the water has to travel from the heater to where it’s required. The energy consumed is therefore for the hot water being used.

Should I install an electric tankless water heater?

Given that it provides an endless supply of heated water, it’s a worthy investment. Unlike other units, they have lower energy bills.

According to the US department of energy, these tankless heaters can save you up to $44 in energy cost per year. Besides being compact, they are efficient safe, and easy to winterize.

Is one electric tankless water heater enough for my house?

Yes provided you choose a model that matches your needs. The best thing to do is to buy a unit that’s capable of handling one shower at a time and can sustain more than 2 showers.

How long will my electric tankless water heater last?

With regular maintenance, an electric tankless water heater can last more than 5 years. So if you want it to last long make sure you take good care of it.

Traditional heater vs. Tankless heater which one is more efficient?

A good tankless water heater is much more efficient than a traditional water heater.

Can I use an electric tankless water heater with hard water?

Yes, you can. However, depending on the model you are using you might need to have it serviced as often as possible to get rid of the lime.

Final thoughts

These are some of the top tankless heaters in the market.  As very powerful heaters they’ll provide you with a high heating system. When shopping for the best electric tankless water heater, consider factors such as your budget and needs. Whether you want to save energy or looking for a good solution, tankless heaters are the best option. Apart from reliability and cost, choose one that can provide you with an endless supply of water.

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