5 Best Whole House Electric Tankless Water Heaters Review

Looking for an excellent appliance to provide endless hot water to your whole house without relying on gas?

Then you should consider investing in the best whole house electric tankless water heater.

Best Whole House Electric Tankless Water Heater

The electric-powered heater is a sustainable alternative to gas heaters, while the tankless design makes them excellent for more compact spaces. It eliminates the worry about ventilation, space or even the threat of gas leaks.

Sounds impressive, right?

This whole house electric tankless water heater review features 5 excellent models available on the market right now.

Let’s get started!

A Quick Comparison of Our Favorites

If you’re in a hurry, check the quick chart below to compare all the essential specs of our recommended 5 top-rated models.

  • Editor’s Choice: Stiebel Eltron Tempra 24 Plus 239222: A whole-house tankless water heater that delivers 1.5 to 4.5 GPM of hot water, features 68 degrees to 140 degrees F output water temperature, uses Industry-Exclusive Flow Control Patented Technology, 15 to 20% less energy than traditional models, and is easy to operate.
  • Best Wall Mount: Ecosmart ECO 18: This unit heats over 2.5GPM with an output of 105 degrees when the inlet water temperature is around 60 degrees F, can be used for 2 showers simultaneously, uses advanced self-modulating technology, saves up to 60% on heating costs, and has a lifetime warranty for residential use.
  • Best for a Small Family: Rheem RTEX-24: A whole house/single point of use tankless water heater that offers a flow rate of 1.5 GPM to 5.9 GPM, maintains exclusive energy efficiency of 99.8%, boasts digital thermostatic control and LED display, and comes with 3 durable copper immersion heating elements.
  • Best Energy Efficient: Rinkmo El18: A compact tankless water heater that delivers water for 2 showers and up to 3 faucets simultaneously, features an easy-to-read temperature display, an auto-protection feature, an abnormal temperature reminder, and outlet temperature more than 167 degrees F and is IPX4 waterproof.
  • Best for both Commercial and Residential Applications: Bosch WH17 Tronic 6000C: This unit instantaneously provides hot water for 1 to 3 applications at a go, has a built-in flow sensor and polymer encase element modulation that controls water temperature, user-friendly interface, provides 2.4 GPM output at 75 degrees F,3.0 GPM at 60 degrees F and 3.5 GPM at 45 degrees F and has a thermal efficiency rating of 97%,

Here Are the Best Whole House Electric Tankless Water Heaters

With so many choices available, selecting the best whole house electric no-tank water heater for your household can seem a challenging task.

Fortunately, we’ve done the hard part for you. This list of the 5 top-rated models will help you to find the exact fit for your home’s hot water needs.

These all are reliable models from trusted brands, and they have a lot to offer.

So, without further ado, let’s check them out.

1. Stiebel Eltron On-demand Tankless Water Heater – Tempra 24 Plus 239222

Tempra 24 Plus 239222

Our Review: Tempra 24 Plus 239222 is an outstanding whole house no-tank water heater from Stiebel Eltron. For those who don’t know, Stiebel Eltron is a German brand- well known for its products with advanced technology and hands-on experience since 1924.

This model is popular for its rapid and excellent performance. It performs the highest standards for reliability and comfort.

Tempra 24 Plus is best suitable for a 1 or 2-bathroom home, apartment, or condo. This on-demand water heater provides continuous and endless hot water when you need it for your whole house. It delivers 1.5 to 4.5 GPM of hot water depending on the temperature rise. The output water temperature is 68-degree to 140-degree F.

The nice aspect is its industry-exclusive Flow Control Patented Technology. It automatically maintains water temperature by adjusting the flow for constant comfort. So your luxury hot showers won’t be interrupted.

Tempra 24 Plus is easy to operate. It features an electronic switch and digital temperature display for accurate temperature setting and maximum energy efficiency. The added feature of this series is its preset temperature and memory buttons.

Importantly, the intelligent auto-modulation helps the unit to save energy, making it eco-friendly. Conveniently, there is a saving monitor that even shows how much you save on energy costs.

It’s worth noting that this model typically uses 15 to 20% less energy compared to traditional electric tank-type water heaters.

The sleek and attractive design of this appliance makes it perfect for installing in different visible locations. It is compact enough to save space. Conveniently, it doesn’t require any ventilation or outlets to pass out the steam that adds to its convenience.

Finally, you can rest assured that the quality workmanship and engineering will keep the unit running for decades!


  • Constant temperature output
  • 0.99 energy factor and no stand-by loss
  • Quality craftsmanship
  • Very sleek structure and design
  • Small and compact to install at any space
  • Totally silent operation
  • Certified against NSF/ANSI 372 for lead-free compliance
  • 7-yr leakage and 3-yr parts warranty
  • Exceptionally supportive customer service


  • Higher demand for hot water than the unit can typically handle, may cause pressure drops.

2. Ecosmart ECO 18 Electric Tankless Water Heater

Ecosmart ECO 18 Electric Tankless Water Heater

Our Review: If you live in an environment where the incoming water temperature is moderately warm (around 62 degrees Fahrenheit or above), the Ecosmart ECO 18 is a model to consider.

It is a solid solution for providing hot water for apartments, townhomes, condominiums, and other whole-home applications.

This no-tank electric water heater delivers endless hot water. The Point-of-use installation and on-demand heating cut down on waiting for hot water. Simultaneously, it saves space, money, time and allows you to reduce your overall energy cost and water usage.

When the inlet water temperature is around 60 degrees, it is capable of heating over 2.5-Gallon per minute with an output temperature of 105 degrees. This capability is equivalent of one sink and one shower head (with a 1.5 GPM flow).

Of course, you can use it for two showers simultaneously when the incoming water temperature is above 70-degree F in warmer climates such as South Florida, South Texas, Arizona, New Mexico, and South California.

The unit comes with digital temperature control that enables you to adjust the water temperature in increments of 1 Degree. It ensures precise and complete control over water temperature.

ECO 18 uses EcoSmart’s advanced self-modulating technology, which means it only uses energy when water needs to be heated. Thus it saves up to 60% on your water heating costs.

This sleek, compact unit is 90% smaller than a tank. The wall-mounted design frees up more storage space on the floor and is.

Ecosmart ECO 18 delivers reliable performance for many years to come. What’s more, the Copper and Stainless components make the unit highly durable. Plus, it has a Lifetime Warranty for residential use.


  • Highly energy efficient
  • Smart design, dependable
  • Energy-saving and cost-effective
  • Precision temperature controls
  • Compact and lightweight
  • Less complicated installation
  • CSA/UL-499 certified & ETL Listed
  • Lifetime Warranty on electronics, exchanger, and element


  • Installation needs to be done by professionals to get the warranty.
  • Not designed for outdoor installation

3. Rheem RTEX-24 Electric Tankless Water Heater

Rheem RTEX-24 Electric Tankless Water Heater

Our Review: Next, we have this excellent choice from Rheem, a well-known American water heaters brand.

RTEX-24 is a Professional Classic no-tank electric water heating appliance that offers continuous hot water on-demand for multiple “whole home” or single point-of-use applications.

It is designed to work most of the Southern USA, like the Southern portions of Georgia, California, Louisiana, Alabama, Florida, and plenty more areas.

If you have a household with three or fewer members, this model would be a good fit. It offers a flow rate from 1.5 GPM to a maximum of 5.9 GPM, depending on temperature rise. RTEX-24 is a smart choice if you need to call for two sinks and one shower or two showers at once.

It delivers a powerful stream of hot water to meet your needs while maintaining an exclusive energy efficiency of 99.8%.

You’ll appreciate its minimalistic appearance and user-friendly design. Its Digital Thermostatic Control and LED display enables you to adjust the temperature in a 1-degree increment.

Importantly, the most advanced self-modulation technology adjusts the amount of energy used to meet hot water demand.

It includes three copper immersion heating elements with a brass top. They are durable and threaded for easy replacement.


  • Compact and stylish design
  • Energy-efficient (99.8%)
  • User-friendly; easy to operate
  • Well-engineered and durable
  • Superior performance
  • Very easy to install
  • Clear installation instructions


  • Installation requires knowledge of installing breakers and running wire.

4. Rinkmo EI18 Electric Tankless Water Heater

Rinkmo EI18 Electric Tankless Water Heater

Our Review: Rinkmo EI18 comes with improved design and state-of-the-art technology. It is an efficient and safe electric water heater that provides instant and on-demand hot water for home use and commercial purposes.

Don’t be worried about the hot water even you have a long shower time. It delivers hot water for up to 3 faucets, two showers simultaneously.

What’s more, there is no need to preheat the water! Within 3 seconds, you can get the hot water you want, with no annoying delay.

The compact design saves space and allows you to install the unit in non-traditional spaces such as the basement, utility room, attic, garage, or even a closet. There is no complicated requirement for installation.

Easy to read digital temperature display shows actual outlet water temperature clearly. Importantly, you’ll always get stable water temperature, no worry of scalding hot water due to reduced flow rate or low water pressure. All thanks to its smart flow sensor and high-quality temperature sensor.

The auto-protection feature immediately cuts off the heating function when it is detected that the outlet temp reaches 167-degree F.

Additionally, it features an abnormal temperature reminder that alarms if the inlet water temp is less than 37-degree F and the outlet temp is more than 167-degree F. Plus, the unit will auto stop if no water is heated.

This model offers 99.8% energy efficiency. Your water heating costs will reduce up to 60%. The smart modulating technology adjusts power-input based on the temp setting and flow rate in real-time. So, there is no chance of sudden temp changes.

Rinkmo EI18 produces heat without direct contact with metals. And there is no mineral buildup, so you don’t need to maintain or fix it and replace the heater coils. It eliminates the expensive maintenance cost in the future.

It is worth noting that Rinkmo EI18 is well-suited for Canada and Northern USA. It also works well for homes in the Southern USA that have Jacuzzi or Roman-style tubs.


  • Easy to install and operation
  • Ensures stable water temp for the whole house
  • No mineral buildup, no maintenance cost
  • Sensitive leakage protection
  • No scalding, leakage, or burnout risk
  • No mineral corrosion inner
  • Fault auto detect
  • Display shows accurately
  • IPX4 waterproof
  • ETL approved


  • No major issues were found.

5. Bosch WH17 Tronic 6000 C Electric Tankless Water Heater

Bosch WH17 Tronic 6000 C

Our Review: Bosch is one of the top-tier brands when it comes to home appliances. Their heating appliances such as point-of-use water heater, on-demand water heater and whole-house electric water heater are popular for high-energy efficiency and versatility.

The Bosch WH17 from Tronic 6000 C series is no different.

WH17 Tronic 6000 C is a good fit for both commercial and residential applications. It heats water instantaneously when and where you need it. It provides endless hot water for 1 to 3 applications at a time- so you never have to be worried about running out of hot water, even at peak use time.

This “on-demand” model eliminates the wait for hot water. Importantly, it provides consistent output temperature. Thanks to its built-in flow sensor and polymer encase element modulation that controls water temp. Plus, the new scale prevention technology allows you to monitor temperature stability and control accordingly.

This electric appliance had a simple, and user-friendly interface. There is an external temperature control knob on the front of the heater. So, you can easily control the temperature.

Bosch WH17 provides 2.4 GPM output at 75°F, 3.0 GPM output at 60°F, and 3.5 output at 45°F temperature rise. With an impressive thermal efficiency rating of 97%, it ensures minimal standby loss.

It boasts a sleek and compact design that not only looks good but also fits nearly any space. The high-grade materials ensure its durability. You can expect it to work for more than 20 years.


  • Superior temperature stability
  • Compact and sleek design
  • Constant output temperature
  • Reduce any stand by water loss
  • Great thermal efficiency
  • Backed by 5-year heating module /2-year parts warranty


  • You may experience a 30-second delay in hot water flow.
  • Tough wiring; only professional installation is recommended.

Best Tankless Water Heater Electric for Whole House – Comparison Chart

Product NamePrice on AmazonMax. Flow Rate (GPM)Activation Flow Rate (GPM)Temperature Range (degree-F)Energy EfficiencyKW
Stiebel Eltron Tempra 24 Plus 239222Check Latest Price4.50.568-14099.824
Ecosmart ECO 18    Check Latest Price4.30.2580-14099.818
Rheem RTEX-24    Check Latest Price5.90.580-14099.824
Rinkmo EI18    Check Latest Price4.50.6680-14099.818
Bosch WH17 Tronic 6000 CCheck Latest Price2.60.695-1319717.3

How to Choose the Best Electric Tankless Water Heater

All of the above-reviewed models will offer you the best value for your money.

In addition to carrying out our own test under different climates, we also evaluate the user-experience of these products’ long-time consumers. This way, we have gained the confidence to recommend those 5 most reliable models.

By this point, I’m sure you’re wondering- among those models which one to get.

Our buying guide can help you in this regard. Before making a purchase, consider the following factors to pick the model that best fits your needs.

Enough chit-chat; let’s go through the shopping guide below.

1. Your Location

It should be noted that the performance of a whole house no-tank model varies depending on weather and situations. In warm regions, the flow rate and temp range are high, while in cold areas, the same model turns into a low rate water heater.

Therefore, you should choose the most suitable model based on where you live. If you live somewhere cold, you should opt for one with freeze protection.

Expert’s suggestion: If you live in the Southern region of the USA, you’re ok with an electric whole house tankless water heater. If you live in the Northern region, this variation might not work properly. Consider picking a regular tank-style unit of the natural gas unit.

2. Size

Buying the right size model is a big decision, and it is critical to find one that can produce enough hot water for your requirements.

Before selecting a model, you need to know EXACTLY what size tankless water heater you would need for your home.

If your no-tank water heater is too small, you may end up taking a cold shower when somebody else in your family is using hot water simultaneously. On the other hand, if you have a too big no-tank water heater, you’ll overpay for excessive performance.

But how to know what size tankless water heater is perfect to meet your needs?

It all depends on your location and groundwater temperature in your region, plus your requirements.

Follow the three easy steps to choose the right size of a no-tank electric water heater.

First, add up the flow rate of each fixture where you intend to use hot water. Consider your peak time usage.

Second, determine the temp rise in your region.

Finally, put all these two considerations all together and pick the model that meets all your requirements.

Notably, the temperature rise is different in different regions across the USA. A Groundwater Temperature Map is helpful to determine the temperature rise in your area easily.

Keep in mind that it is wise to invest in a slightly oversize unit than buy the one that can’t supply enough hot water.

3. Installation

If your home already has a tank-type heater and plan to replace it with a no-tank model, it is important to consider installation. In this case, you have to reconfigure the water piping, electrical wiring, etc.

4. Energy efficiency

A no-tank whole-house electric water heater requires to consume a significant amount of water each minute during operation. Therefore, if you install a high energy-efficient type model, you can save a lot of money each month on your heating bills and your water bills.

5. Heater Warranty

In general, no-tank water heaters tend to offer long-term reliability. Most of the models are designed to last up to 20+ years, and the majority of the internal components are replaceable or serviceable.

However, almost all brands offer their own unique warranty policies. So, it is essential to check the manufacturer’s terms and conditions.

Typically, most brands require the heater to be replaced or serviced if purchased from a genuine source. And warranties of these products are valid only if you purchase them from an authorized dealer. What’s more, the warranty is only for a specified period.

Make sure you have purchased it authorized dealer and have proof of the purchase.


Our reviewed 5 models have got the best feedback from our team of experts and the verified users.

So, you can buy them with confidence.

Pick the best whole house electric tankless water heater from our comprehensive list and take your water heating to the next level!

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