Best Whole House Electric Tankless Water Heater 2021 – High Flow Rate

If you are using a classic tank water heater, believe me, it is a waste of space, an investment, and electricity. All you need is to upgrade now as the demand for a whole-house electric tankless water heater is continuous to grow in the market. 

More technological advancements that are focusing on higher efficiency in the whole house tankless water heater are coming. We have discussed some of the best whole-house electric tankless water heaters. The models we have discussed and reviewed are already cost-saving, and highly-efficient.

best whole house electric tankless water heater

Top 10 Best Whole House Electric Tankless Water Heater Reviews

As there is high competition on the market, it becomes nerve wrenching to find out the right whole house tankless hot water heater. We hope our article will help you finding out the best electric tankless water heater for the whole house.

Image Product Details   Price
ecosmart 27 electric tankless water heater
EcoSmart ECO 27 Tankless Water Heater
Max GPM: 6.5

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Stiebel Eltron Tankless Water Heater – Tempra 24 Plus – Electric
Stiebel Eltron Tempra 24 Plus 
Max GPM: 5

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Rheem RTEX-24 24kW 240V Electric Tankless Water Heater
Rheem RTEX-24 Electric Tankless Water Heater
Max GPM: 5.9

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BLACK + DECKER 27 kW Self-Modulating 5.3 GPM Electric Tankless Water Heater
BLACK + DECKER 27 kW Self-Modulating
Max GPM: 5.3

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Rinnai RL94EP RRL94eP
Rinnai RL94EP Tankless Water Heater
Max GPM: 9.4

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Takagi T-H3-DV-N Indoor Tankless Water Heater
Takagi T-H3-DV-N Natural Gas Indoor
Max GPM: 10

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Rheem RTEX-18 18kW 240V Electric Tankless Water Heater Rheem RTEX-18 Electric Water Heater Max GPM: 4.4

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Stiebel Eltron Tankless Heater – Tempra 36 Plus – Electric, On Demand Hot Water Stiebel Eltron Tempra 36 Plus Max GPM: 7.5

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rinnai RL 94en 9.4GPM
Rinnai RL94EN Tankless Water Heater
Max GPM: 9.4

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Rinnai V65IN Tankless Water Heater, Large, V65iN-Natural Gas
Rinnai V65IN Tankless Water Heater
Max GPM: 6.5

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1. EcoSmart 27 – Best Electric On Demand Water Heater Overall

 EcoSmart 27 as best electric tankless water heater for whole house
  • Savings of up to 50% on water heating costs
  • Digital temperature control in 1-degree increments
  • Compact size saves valuable storage space
  • Designed for efficiency, durability and easy replacement

Ecosmart is one of the reliable brands that manufacture the best whole-house tankless water heater for both homes and businesses. Their heaters enable you to enjoy your everyday living by sharing the warmth of endless hot water.

A very popular and trusted brand Ecosmart provides you a whole house electric tankless water heater. Ecosmart offers its customers a wide range of models with different capacities according to your specific demands.

The discussed model is the second most powerful Ecosmart electric tankless water heater, following the Ecosmart ECO 36 KW. Other than that, this ECO 27 features inlet thermistor to sense the ground water temeprature and acitvates the self-modulation technology accordingly.

Equipped with inlet thermistor to sense the incoming water temeprature

Although, the manufacturers claim that this model is enough efficient to provide you up to 6.5 gallons of hot water per minute. But according to the feedback from the multiple owners, the real flow rate is about 5.6 GPM in the warmer climates.

However, if you are living in colder climates, where the temperature of the groundwater is as low as 5°C, you must not expect more than 3-3.5 GPM.

This outstanding EcoSmart ECO 27 Electric Tankless Water Heater can easily handle 3 showers. You can use this water heater for up to 3 bathrooms because of its 5+ GPM flow rate.

PROS

  • Compact design saves more storage space
  • Easy to install and use
  • Highly-efficient
  • Low efficient flow rate

CONS

  • May corrode if not maintained properly
  • Warranty issues

2. Stiebel Eltron Tempra 24 Plus – Whole Home Tankless Water Heater

Stiebel Eltron 24 plus best whole house electric tankless water heater reviews
  • Exclusive Advanced Flow Control German patented technology
  • Use 15-20% less energy compared to conventional heaters
  • Compact size saves valuable storage space
  • Venting free electric heaters

Tempra 24 Plus Whole House Electric Tankless Water Heater manufactured by Stiebel Eltron. Stiebel Eltron is a pioneer and leader in water heating technology for over 90 years.

Stiebel Eltron Tempra 24 Plus is a highly-efficient electric tankless water heater. This water heater is suitable for two bathrooms.

This whole house electric tankless water heater is designed on advanced Flow Control technology. This technology makes sure that when the demand for hot water is higher than the unit can typically handle, it prevents showers or the appliances from getting cold water by reducing the pressure and by keeping the hot water hot.

Because of this Advanced Flow Control Technology, you may get less hot water but it would not be colder as it sometimes happens with other tankless water heaters. The best of all, it saves on your energy bills.

estimated yearly energy use

This water heater can provide 1.5 to 4.5 GPM of hot water depending on the temperature rise. That’s enough to supply hot water to 2 showers that are running at the same time. And it will supply water without temperature fluctuations and pressure drops.

Moreover, this whole house instant water heater is extremely quiet and silent. It will not disturb your home environment.

The compact design of this water heater saves you a huge amount of space compared to other traditional storage water heaters.

PROS

  • Easy to operate
  • Small CO2 footprint
  • Extremely silent operations
  • Convenient Digital Display
  • Stable Temperature Output

CONS

  • If sized not correctly, may cause pressure drops

3. Rheem RTEX-24 Electric – Best Whole House On Demand Water Heater

Rheem Rtex 24 best whole house tankless water heater
  • ON/OFF Dial Control with adjustable digital temp display
  • Self-modulating power control
  • Up to 5.9 GPM for RTEX-24
  • On demand, consistent and continuous hot water

This Whole House Electric Tankless Water Heateroffers quick and continuous hot water without temperature fluctuations. This water heater is ideal for a single point of use or multiple applications.

The water heater is designed with robust copper immersion heating elements with a brass top. This highly-efficient design increases its durability.

Moreover, it has a feature of digital temperature control that allows you to set temperature in increments of 1°.

Ultimately, Rheem RTEX-24’s flow rate ranges from 1.5 to up to 5.9 GPM, depending on the temperature rise. This feature makes this water heater a perfect choice for a household with lighter hot water demand. It would be a good fit for your house if you have fewer people at your place.

This outstanding tankless water heater draws 100 amps. It is designed with three heating chambers so you would need 3 double poles 40 amp breakers.

Rheem 240 three heating chambers

PROS

  • Compact design that saves space
  • Accurate digital controller
  • Endless hot water
  • Robust and durable
  • Easy installation
  • Eco friendly, durable with lifetime warranty.

CONS

  • Takes 10-15 seconds before to get fully hot

4. BLACK + DECKER 27 kW Self-Modulating Heater – Best Electric On Demand Water Heater

Black + Decker whole house tankless water heater
  • On demand hot water heater for whole house
  • Save up to 50% on your water heating costs
  • Ideal for commercial or residential use
  • Durable stainless steel, non-corrosive internal canisters and piping

You can now enjoy endless hot water without the wait or worry of ever running out. You can do this by installing this Black and Decker Electric Tankless Hot Water Heater.

The quality service and excellent performance of this water heater are the reasons for its popularity. The durable design of this Black and Decker tankless water heater provides this an edge over other models. 

This whole-home tankless water heateroffers some of the best performance for the price. You can buy this at a very reasonable price.

If we see its specifications, it can provide about 3.3 GPM in the colder climates. However, it can provide up to 5.3 GPM of hot water in the southern states.

Moreover, this electric tankless water heater is enough to supply hot water to 2 bathrooms with two showers running at the same time.

A normal tank water heater works constantly to keep water hot that wastes so much energy. But this Black+Decker electric water heater saves both money and energy by heating water only when you need it.

specification guide  of BLACK + DECKER 27 kW Self-Modulating Heater

Additionally, the compact and sleek wall-mounting design will have you regain the space that your old water heater took up.

PROS

  • High-quality Performance
  • compact and sleek wall-mounting design
  • Saves energy and water
  • Hot water heater for ideal for whole house

CONS

  • Limited temperature range
  • Warranty issues has found

5. Rinnai RL94EP – Whole House Instant Hot Water for Large Families

Rinnai RL94 ep whole house on demand water heater
  • Endless hot water for your entire home
  • Greater energy efficiency and lower energy costs
  • Tankless Non Condensing Water Heater
  •  Parts of Rinnai Tankless water heater are replicable 

The Rinnai RL94eP is an effective and robust unit that suits many properties. It will benefit you in many cases i.e energy-saving etc.

This whole house water heatercan supply up to 9.4 GPM. The supply rate varies from region to region. If you live in a colder climate, it will deliver you a full 9.4 GPM. However, in extremely cold climate areas, your GPM might be a little less.

This outstanding tankless water heater requires up to 199,000 BTUs. This water heater has an 83% thermal efficiency.

The RL94eP weighs only 46 pounds, which not only make it the most compact on the market, but still light and portable enough for most homeowners.

Since it is a propane unit, RL94eP works with a system of internal sensors and heat exchangers. This unit has a burner that uses a live flame. This feature makes it a very powerful tankless water heater that can serve multiple bathrooms at a time.

Salient features of Rinnai RL94EP

PROS

  • A powerful propane water heater that can service multiple bathrooms at a time
  • Can be used in both commercial and residential settings
  • Comes up extended warranty that covers its parts, installation, and labor
  • Easy to install and operate

CONS

  • Not the most affordable model on the market
  • Requires venting system

6. Takagi T-H3-DV-N Natural Gas Tankless Heater – Best Value For Money

Takagi T whole house gas tankless water heater
  • On-demand usage, energy conservation
  • Computerized safety features
  • Ultra-Low NOx Emissions
  • Includes troubleshooting diagnostic codes 

Takagi T-H3-DV-N is a well suited indoor tankless water heater for residential and commercial applications such as small restaurants and salons.

If you have natural gas lines in your home, then this Takagi T-H3-DV-N Natural Gas Indoor Tankless water heater is the perfect choice to serve as a whole house heater.

This outstanding water heater can heat up to 10 GPM of water. This means you will have more than enough hot water for taking hot and long showers.

This model of Takagi has an energy factor of 0.95 for natural gas that makes this model one of the best water heaters that saves maximum energy.

The higher rating of heating water serves four bathrooms at a time without fail.

Sadly, during excessive use of hot water, you may experience 1 to 2 degree drop of water temperature for a short period. 

This model comes with advanced control features. This durable machine is long-lasting and highly efficient.

Moreover, this natural gas indoor water heater comes with a 15-year limited warranty for the residential model. And a 10-year long warranty for the commercial model. They also have a 5-year limited parts warranty.

The unit requires a special venting, professional installation, and pipe system, which may be a bit expensive. But all of these cover this with its incredible energy efficiency.

PROS

  • High volume output
  • Low Nitrogen Oxide Emission Levels
  • Performs flawlessly under challenging conditions
  • Water flow meter shows exact water flows rate
  • Long-lasting 

CONS

  • Very expensive to install
  • Has temperature issues at some regions

7. Rheem RTEX-18 Electric Tankless Water Heater – Amazon’s Choice

Rheem Rtex 18 whole house electric tankless water heater
  • External digital thermostatic control with LED display
  • Most advanced self-modulation
  • Durable Copper immersion two heating elements
  • Threaded for easy replacement

Among top rated electric tankless water heaters, Rheem RTEX-18 water heater offers quick and continuous hot water that is on-demand for single point-of-use or multiple applications. This is one of the best whole house electric tankless water heaters.

The maximum flow rate of this water heater is 4.4 GPM. Due to this flow rate, this water heater can deliver hot water to two showers or one shower with one faucet in colder climates.

The water heater is designed with robust copper immersion heating elements with a brass top. This design gives it durability and makes it long-lasting. Additionally wire requirements of each Rheem model is different.

How to wire Rheem RETEX18

The unique feature of digital temperature control allows you to set temperature in increments of 1°. The water heater has a 99.8% energy efficiency rating.

The water heater has an external thermostatic digital control that has a LED display. With the help of this feature, you can adjust the temperature between 80 degrees F to 140 degrees F.

This whole house water heaterhas electrical requirements of 18kW, 75 amps, and 240 volts.

PROS

  • Self-modulation unit
  • Maximum temperature control
  • Copper-immersed heating elements
  • Easy replacements
  • Easy to install and use

CONS

  • Cant handle the high flow

8. Stiebel Eltron Tempra 36 Plus Tankless Heater – Best Advanced Flow Control Patented Technology

Stiebel Eltron 36 whole house tankless hot water heater
  • Continuous and unlimited supply of hot water
  • Sleek design saves space
  • Electronic switch activated for virtually silent operation
  • 7 Years leakage and 3 years parts complete warranty

The Stiebel Eltron Tempra 36 plus electric water heater is ideal for those who want to save energy.

This Water Heater features an exclusive Advanced Flow Control German Patented technology invented by Stiebel Eltron. This technology automatically maintains the water temperature for constant comfort.

The maximum flow rate of this Stiebel Eltron Tankless water heater is 7.03 GPM. Due to this high flow rate, this water heater can deliver hot water for three to four washrooms at a time. Moreover, the minimum water flow to activate this unit is 0.77 GPM.

The water heater will reduce flow slightly if the demand for hot water exceeds. This feature ensures that hot water will be uninterrupted.

This outstanding water heater will typically use 15-20% less energy as compared to any other conventional electric tank water heaters. You can also save more energy by changing your home usage habits. The Tempra Plus series have more advanced features than Tempra Trend.

Comparison chart of tempra plus and tempra trend

The Stiebel Eltron Tankless Water Heater works quietly and does not produce sound while operating. This feature makes this water heater ideal for homes that have kids.

The compact and small design of this Stiebel Eltron water heater makes it able to fit in small spaces. Moreover, it will require no venting.

The outstanding water heater comes up with a 7-years leakage warranty and a 3-year warranty on parts.

PROS

  • Constant energy saving
  • Digital display for maximum energy efficiency
  • Excellent flow rate in economical pricing.
  • Continuous supply of hot water
  • Compact and sleek design
  • No venting required

CONS

  • Water temperature is not consistent
  • Requires professional installation

9. Rinnai RL94EN – Top Rated Tankless Water Heater

Rinnai RL 94en whole house gas tankless water heater
  • RL94eN HE+ High Efficiency Tankless Hot Water Heater 
  • Up to 9.4 GPM hot water flow rate
  • Circ-Logic technology allows you to set recirculation patterns
  • Affordable, durable and reliable

A Rinnai Tankless water heater provides you continuous hot water and will never leave you in the cold.

This Rinnai Tankless Water Heater is designed with ThermaCirc360 technology that recirculates hot water through your pipes and provides you hot water fast.

The capacity of this water heater is up to 9.4 GPM of hot water. The RL94eN is capable of supplying hot water to as many as five plumbing and appliance outlets.

On the positive side, the whole house instant water heater will save an average of 87,000 bottles of water per person, per year.

The compact design of this water heater allows you for installation in non-traditional spaces such as the crawl, attic space, or even a closet. This small suitcase size water heater will save 16 sq. foot of space.

Significantly, this efficient compact design water heater cuts CO2 emissions, uses less energy, and conserves water. This water heater uses 40% less energy than a traditional tank because it only heats water when you need it. Rated by a Uniform Energy Factor (UEF), this tankless water heater is highly energy efficient, saving you from expensive power and water costs.

Energy efficient

Every part of this Rinnai Water heater is replicable and replaceable. Due to this feature, every component can easily be swapped and replaced vs. buying a whole new system. The suitcase-sized compact wall units fit neatly in, freeing up more usable areas in your home.

As far as the life is concerned, the average life expectancy of this outclass the whole house on-demand water heater is 20 years. While an average life expectancy for a traditional tank is 8-10 years. It is expected that this water heater will work double as compared to traditional tank water heaters.

The capacity of this water heater is up to 9.4 GPM of hot water. The RL94eN is capable of supplying hot water to as many as five plumbing and appliance outlets.

PROS

  • Efficient compact design water heater cuts CO2 emissions
  • ThermaCirc360 technology recirculates hot water
  • Capable of supplying hot water to 5 appliance outlets
  • Up to 9.4 GPM capacity

CONS

  • Unit is expensive
  • Requires a minimum flow rate to operate

10. Rinnai V65IN Tankless Water Heater – Best Budget Tankless Model

Rinnai v65in whole house instant hot water
  • Natural Gas: Indoor Installation Only
  • Control-R 2.0 mobile app features put the system into vacation mode
  • Compact design saves 16 sq. foot of space
  • Use 40% less energy than traditional tanks

It is a perfect combination of comfort, high-efficiency, and value in a natural gas water heater from the manufacturer Rinnai.

Notably, this model from Rinnai is ideal for small to medium homes. The compact design of this water heater is easy to install, perfect for indoor locations, and reliable.

space saving design

This Rinnai V65IN water heater has a maximum hot water flow rate of 6.5 GPM. It will supply hot water to up to three fixtures simultaneously. 

Additionally, this water heater is equipped with ThermaCirc360 technology. This technology recirculates hot water through the pipes and accelerates the delivery of hot water to showers. With the help of this feature, you can get hot water in the blink of an eye.

Rinnai Water heater only heats water on demand, so it uses less energy than any other traditional water heater. This feature makes it able to cut down CO2 emission as well as gas consumption.

The most interesting thing about this model is that all of its parts are replaceable. So if any part breaks down, you can easily get its replacement. 

Furthermore, the product comes with a warranty of 120 months heat exchanger, 12 months labor, and 60 months parts.

PROS

  • Compact Body
  • Convenient Control Layout
  • Replaceable Components
  • Long warranty 

CONS

  • Require odd exhaust venting

Advantages Of Best Whole House On Demand Water Heater

Advantages of whole house tankless water heaters

FAQ

Can a tankless water heater work for the whole house?

Whole-house tankless water heaters feature to meet the high demand of hot water. They usually have excessive GPM flow rate ability. Therefore, they ensure the delivery of hot water to many fixtures at a time without the fear of running out of hot water during usage.

In a like manner, you can take long hot shower while the kitchen sink, dishwasher and laundry applications are turned on.

As far as the heater’s capacity is concerned, the size of whole-home tankless water heater depends on the flow rate it has. As different water appliances delivers different amount of water. So, the type and number of fixtures in simultaneous use affects the supply of hot water.

Unfortunately showerheads have the high flow rate than other appliances. So, if you have many people in your family, you must go for the whole-house tankless heater with maximum flow rate. So, you can access hot water fearlessly whenever you need it.

How much does a whole house tankless water heater cost?

As whole house tankless heaters come with large flow rate capacity to fulfill huge demand of hot water, so , they have relatively high cost than others.

The price range for whole-house heaters ranges from $1000 to $ 3000 including the fuel type and professional installation.

Why is tankless water heater installation so expensive?

There are many factors involve in the high price of large sized tankless water ehaters. Like electric panel upgrade, gas line upgrade and qualified installation by a professional.

As a matter of fact, larger heaters require huge supply of gas than traditional heaters. So, you need to spend considerable amount of dollars on it. Similarly, if you go for electric tankless models, you need to upgrade your electric panel system which is a deal of thousand dollars.

Moreover, you have to spend a lot on certified installation by professionals.

Daniel Adley is an experienced and skillful plumber having more than 20 years of experience. He is a skillful plumber who passionately repaired and optimized water appliances of large buildings, offices and homes. He would efficiently identify plumbing and maintenance issues.

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