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The Best Electric Tankless Water Heaters

Jennifer Hansen
Last Updated on
by Jennifer Hansen

Hot water storage tanks can sometimes be convenient if they are pre-existing with your house, but they take up lots of space, waste energy, and can cost a lot of money over the years.

To save yourself a headache and to cut your energy bills, many people are switching over to all-electric tankless heater systems.

If you are interested in modernizing your home or office water heating system, we recommend checking out our list of the best electric tankless water heater reviews.

Not only will these energy-efficient heaters meet your water needs, but your wallet will thank you after you start saving every month on your utility bills.

Also , Have a look at our buyer’s guide to the best tankless water heaters

Best Tankless Electric Water Heaters
Editor’s Choice
  • Power Rating (kW): 36
  • Dimensions (inches): 17 x 19 x 3.8
  • Weight (lbs): 18.35
  • Power Rating (kW): 36
  • Dimensions (inches): 16.54 x 4.61 x 14.53
  • Weight (lbs): 19
Budget Choice
  • Power Rating (kW): 13
  • Dimensions (inches): 4 x 9 x 13
  • Weight (lbs): 4
  • Power Rating (kW): 26.9
  • Dimensions (inches): 15.5 x 4.5 x 12.5
  • Weight (lbs): 19.5
  • Power Rating (kW): 11.8
  • Dimensions (inches): 12 x 10 x 5
  • Weight (lbs): 2
  • Power Rating (kW): 6
  • Dimensions (inches): 14.29 x 12.8 x 4.41
  • Weight (lbs): 6.75

The Best Electric Tankless Water Heater Reviews

1. Ecosmart ECO36


The all-new Ecosmart ECO36 is arguably the most energy-efficient water heater on the market. Using patented technology, this Ecosmart model can slice your heating bills in half due to its supreme cost-cutting abilities.

Featuring self-modulating temperature control mechanisms, this water heater can detect temperature changes of less than even one-degree Fahrenheit.

In our experience, the Ecosmart ECO36 is one of the best electric tankless water heater models if your main priority is saving money and conserving space in your house. With an impressive 0.3 gallons per minute (GPM) activation flow, this heater unit can easily replace most household heating tanks at a fraction of the cost.

Overall, a 6 GPM tankless system design provides an endless supply of hot water at the convenience of your fingertips. Best of all, this product is backed by a lifetime warranty for residential use, making it a foolproof investment in the long term.

Plus, the recommended breaker usage is four by 40 amps, which proves that it runs on a low supply of electricity.

This tankless water heater is up to 90% smaller than the industry standard water heater; making is the perfect addition to a small apartment or starter home. Based on our experience testing this model, you will be enjoying this electric heater system for many years to come.

  • You can save up to 90% of space compared to tank-type systems
  • It can read temperature adjustments of under one-degree Fahrenheit
  • Quick installation process makes for easy setup
  • Copper and stainless steel components lead to greater energy efficiency
  • Bright LED indicator lights make the ECO36 simple to use
  • The warranty clauses are complicated and can become annulled
  • There are some reports of water leaking and dripping on the floor


When it comes to water heating and cooling, no product is perfect. Unfortunately, every category of product is plagued by its share of drawbacks and design defects and the Ecosmart ECO36 is no exception.

However, the question, in this case, is whether the benefits outweigh the setbacks and we think the verdict comes out in the ECO36’s favor for those shoppers who put a premium on size and compactness.

2. Stiebel Eltron Tempra Plus


Powered by 150A of electricity, the Stiebel Eltron Tempra Plus is one of the leading water heaters for those who have migrated away from the tank-type heating systems. If you want the best electric tankless water heater on the market, the Tempra Plus is one of the few options that stand out from the rest.

Simply by switching to a Tempra Plus, you can save between 15 and 20 percent off the water portion of your electric bill. Plus, its Easy Setup function makes the Tempra a breeze to install and have operational. Requiring electrical service for up to 300A at peak hours, the Tempera Plus makes the most of small energy supply to provide you with an abundance of hot water.

Digital temperature control ensures that even the slightest alterations in temperature are registered by the heat sensors in this heater. In other words, the heater’s internal sensors can measure small changes in heat levels to make sure you receive perfectly heated water every time.

Rivaling even gas-powered heating units, this system can flow nearly five GPM to supply a copious amount of hot water to all household faucets in an efficient manner. Regardless of your household size and water needs, this heater is an excellent choice as it is more than capable of satisfying whatever demands you throw at it.

  • Dual stainless steel build is highly durable and corrosion resistant
  • Energy Star certified and eco-friendly
  • Suits a variety of uses and applications
  • Very small and highly affordable device
  • It can easily be installed by one person
  • Pure performance metrics lag behind some competitor models
  • Does not perform very well in frigid climates


There are plenty of good aspects of this tankless water heater, with a handful of unfortunate drawbacks that hold it back from reaching the top of the industry. Sitting at nearly 5GPM, this heater is more than capable of handling a 1.5-bathroom hot water demand.

If you live alone or share a one-bathroom apartment, this heater might be the ideal choice for you.

3. Rheem RTEX-13


The Rheem RTEX-13 is a fantastic all-in-one heating solution for your household water needs. Unlike competitor systems, this model is 99.8% energy efficient due to its external temperature control mechanism that adjusts temperature settings in increments of only one-degree Fahrenheit.

With this water heater, you benefit from a relatively quick and painless installation process. Since the RTEX-13 is bundled with three feet of electric cable and NPT adapters, the setup process can be completed in a matter of hours. One added benefit of investing in an RTEX water heater is that the device features bright LED indicators for simple adjustments and tweaks.

If you want a straightforward tankless water heater system that runs on electricity alone, the RTEX-13 may be the solution for you. Backed by a best-in-class manufacturer’s warranty and premium threading for a no-hassle product replacement, this Rheem product is among the best value tankless water heaters on the market regarding efficiency and overall value.

  • Excellent value at an affordable price point
  • It can pay for itself in under two years due to efficiency improvements
  • Boasts GPM metrics that rival gas-powered systems
  • Ultra-compact form factor helps save space
  • Works well in multi-unit buildings where there is increased demand
  • The flow metrics sometimes do not live up to advertised levels in cold climates
  • Works best when only one shower is in use at a time


As a relatively new technology, it is understandable that the Rheem RTEX-13 is marked by an assortment of both positive and negative qualities. However, we think that the RTEX model’s impressive GPM performance and highly compact build make it a superior choice for most larger households.

4. Bosch WH27


You get what you pay for with the Bosch WH27, which delivers premium performance at an upscale price point. Although this electric water heater will cost you more at checkout than most rival devices, the Bosch WH27 is worth every penny since it produces a nearly endless supply of hot water at a minimal energy consumption rate.

At 97% thermal efficiency, you would be hard-pressed to find a superior water heater on the market today. While it is true that there are more affordable options available, the WH27 ranks among the best electric tankless water heater devices thanks to its highly efficient nature and superior temperature control capabilities.

Weighing less than 20 pounds, this electric water heater can be easily mounted on any household wall or surface. In a little more than an hour, we were able to install the WH27 with minimal resistance. Once it was up and operational, we ran into no issues or setbacks when using the device and getting it to supply our household water system.

When you switch over to the WH27 from your old clunker hot water storage tank, you can knock two-thirds off your monthly hot water bill. Sounds like a great deal, huh? Plus, if anything goes wrong with your system, you can return it at no cost thanks to its fantastic manufacturer’s warranty policy.

  • Features a compact and lightweight design
  • Patented element modulating control unit technology self-regulates temperature
  • Suitable for household or commercial applications
  • Operates quietly and with low power consumption required
  • Requires no venting or external air flow
  • Requires a 240-volt breaker outlet
  • Often results in a slight delay of 20-40 seconds
  • Costly to repair
  • Not as affordable as rival electric hot water systems


Built by one of the foremost manufacturers of household electric appliances in Europe, the Bosch WH27 is a marvel of German engineering. Despite its technical superiority and impressive build design, there are still several aspects of the WH27 that we think could do with a little refining.

However, we believe that the WH27 is a great choice for those who need a quiet and low-profile water heater at a low cost.

5. Titan SCR2 N-120


The veteran water heater manufacturers at Titan have outdone themselves yet again with the Titan SCR2 N-120. Constructed in collaboration with Niagara Industries, the N-120 is a speedy 220-volt electric and 100% tankless water heater built to supply your home or office with an abundance of hot water at a low cost.

At only eight pounds in weight, there is virtually no wall or surface that the N-120 cannot be installed on. Consequently, there is no excuse not to install the N-120 in your office or household since it is tailored for all environments. Plus, its tan steel finish adds some personal flair to an otherwise classic design that blends in well regardless of the room’s style.

For continuous hot water supply, we suggest trusting the experts at Titan to provide you with 50-60 Hz or 11.8 kW of scorching-hot water flow. Best of all, this heater will heat your water supply when you require it only, so you do not have to worry about wasting power by unneeded heating water.

  • Despite its compact form factor, the Titan can pump out 4.0 GPM
  • Excellent manufacturer’s warranty provides comprehensive coverage
  • More affordable than other brands, and easy to install
  • Has a great energy efficiency rating of 99.5%
  • It looks great when planted on the wall
  • It requires an inlet water temperature of 65 degrees Fahrenheit
  • Not a great choice for cold-weather climates
  • Water temperature starts high at 105 degrees Fahrenheit


There is a healthy mix of drawbacks and praise worthy aspects of the Titan N-120. When they lay them out side-by-side, however, it is clear that the good vastly outweighs the bad.

Based on our research we would recommend the N-120 to families that are concerned about their energy bill prices and need a fast solution for cutting costs.

6. Sio Green IR260 POU


It is not every day you come across a high-tech infrared tankless water heater. But, today, the Sio Green IR260 POU is taking the market by storm for boasting exactly those features while saving customers money every month on their gas and electric bills. With models ranging from 30A and 3.4kW up to 80A and 18kW, you can rest assured knowing that there is a device available that perfectly suits your household needs.

Using innovative technology, the IR260 POU has earned its place as one of the best electric tankless water heater systems. Featuring a no-coil and no-metal design, you never have to worry about maintenance or corrosion when dealing with this device. Instead, you simply install it within minutes of purchase and enjoy your monthly cash savings.

At less than 20 inches in length, this device boasts an impressively compact form factor. In our experience, we were able to install this system virtually anywhere in our house with ease—from small kitchen cabinets to underneath the bathroom sink. If you need a budget-friendly, space-saving water heater solution, you cannot go wrong with the IR260 POU.

  • 100% Satisfaction Guarantee or your money back
  • Requires only 30A to produce up to 6.0kW or heating power
  • The device pays for itself in less than two years
  • It only heats water as you use it, causing no unwanted waste
  • Infrared heating eliminates the need for quartz-based components
  • Its small size does not lend itself well to large multi-unit households
  • Low 1.5 GPM flow rate can result in a limited hot water supply during peak demand


Although it has many design features and perks going for it, there are some unfortunate drawbacks that hold the IR260 POU back from achieving “perfection” status.

Regardless, the IR260 POU makes for a formidable solution if you want a no-risk water heater that does not require a lot of energy to maintain itself.

7. Sio Green SIO18


Another excellent infrared-based tankless water heater by the professionals at Sio Green, the Sio Green SIO18 provides plenty of hot water at a fraction of the regular cost. This system uses an infrared construction to supply commercial and residential buildings with limescale and algae-free hot water all day and night.

Using patented technology, the SIO18 can provide hot water to your house without having to rely on any dangerous components or volatile metals such as quartz. Instead, all you get with this system is clean, well-functioning tankless water heating and loads of monthly cost savings on your bills.

Given its small, lightweight form factor, the SIO18 can be installed anywhere in the house and easily concealed in cabinets or drawers. Best of all, those interested in maximizing their long-term cost savings will appreciate how this product is so cost-efficient that it can slash monthly utility bills in half due to superior insulation and thermal efficiency ratings.

  • Pays for itself in as little as 18 months
  • Comprehensive 100% Satisfaction Guarantee plus manufacturer’s warranty
  • Quartz-free design prevents limescale and calcium buildup
  • Uses only 110-220V electric supply
  • It can be installed almost anywhere in the house
  • It sometimes struggles to provide hot water to more than one shower at a time
  • The temperature sensor is not always accurate to the closest degree


Although the Sio Green lineup of infrared tankless water heaters is known for their premium quality and high cost-effectiveness, they also suffer from setbacks that are common in the industry.

In our opinion, we think the a Sio Green water heater is the perfect choice for those who need a small unit that does not consume a lot of electricity in standby mode.

Pre-Purchase Considerations

Believe it or not, there is a lot that goes into purchasing a tankless water heater. Although they rarely make the list of a household’s top home improvement priorities, going tankless should not be taken lightly as it can result in serious cost savings over the lifespan of the house.

To help you find the best electric tankless water heater for your household, follow these quick tips:

  • Invest in heaters with non-metallic elements to prevent calcium or limescale buildup
  • Flow rates of 4.0GPM or higher allow for multiple showers to be used simultaneously
  • Compactness is important; make sure your heater is small enough to fit in tight spaces
  • Look for devices with energy efficiency ratings of 98% or higher
  • Opt for systems with a lifetime warranty or a Satisfaction Guarantee


In sum, it is important to remember the big picture when shopping for the best electric tankless water heater. This is because it is easy to forget why you are upgrading when you get lost in the small details.

Ultimately, a small and reputable  heater will provide you with loads of cost savings every month—so shop around and start saving money and space today.

If you’re wondering how much a water heater would last you , have a look at our article here.

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About Jennifer Hansen
Jennifer Hansen
Jennifer is a clean water enthusiast and the lead editor of Water Filter Spot and created this website several years ago to share information that she's been researching in this industry for over 20 years.Jennifer studied environmental resource science in college and studied Western US water issues, including water policy, water rights, water pollution and environmental concerns.
Jennifer Hansen