Best Whole House Electric Tankless Water Heaters

25 Products Evaluated
15 Hours of Research
2 Experts Interviewed
343 Reviews Analyzed

If you’re living in a cold climate and the hot water demand is high, I personally wouldn’t recommend buying a whole house electric tankless water heater vs a natural gas tankless water heater. It’s hard for an electric unit to keep up during the cold winters when the temperature drops below freezing. You would be better off with a whole house gas tankless water heater and additional point of use units.

But if you live in Florida, Texas, California, or another southern state where the groundwater temp is higher, a whole house electric tankless water heater is a great choice and an opportunity to save space, money, and enjoy the luxury of endless hot water.

Anyway, you are here for the best whole house electric tankless water heaters, right?

If you’re in hurry and just want a straight answer, we recommend you to look at this model:

EcoSmart ECO 27 Electric Tankless Water Heater:
  • Max. Flow Rate: 5 GPM
  • Activation Flow Rate: 0.25 GPM
  • Dimensions: 17″H x 17″W x3.75″D
  • Service Requirements: 113 amps (3 double pole x 40 amp breakers)
  • 99.8 Energy efficient
Read Verified Customers Reviews

For everyone else we prepared several thorough reviews of the best whole house electric tankless water heaters. Let’s start!

Every brand we mention here have several sizing options. If you liked the brand but not sure about the size, feel free to check out other sizing options by clicking the “Check price” link.

Best Whole House Electric Tankless Water Heater Reviews

For our list, we picked and reviewed the models that got the best feedback from our experts, our readers, and the verified owners. We also tried to pick the best brands that our professionals have worked with.

These all are trusted brands and tested models, but before buying one, you need to make sure that it’s the correct size for your needs. For more information refer to the sizing section or read through our complete guide on how big of a tankless water heater you would need for your needs.

1. Ecosmart ECO 27 kW Whole House Electric Tankless Water Heater

Ecosmart ECO 27 - Best Whole House Electric Tankless Water Heater
Ecosmart ECO 27 – Best Whole House Electric Tankless Water Heater
EcoSmart ECO 27 Electric Tankless Water Heater:
  • Max. Flow Rate: 5 GPM
  • Activation Flow Rate: 0.25 GPM
  • Dimensions: 17″H x 17″W x3.75″D
  • Service Requirements: 113 amps (3 double pole x 40 amp breakers)
  • 99.8 Energy efficient
Read Verified Customers Reviews
Pros
Easy to operate
Lifetime warranty
Low activation flow rate
Super efficient
Cons
Warranty conditions (licensed installation required)

Ecosmart is a very popular and trusted electric tankless water heaters brand. It offers a wide range of models with different capacity for your specific demands. Ecosmart ECO 27 kW is the second most powerful Ecosmart electric tankless water heater, following the Ecosmart ECO 36 kW.

According to the manufacturer, it is able to provide up to 6 gallons of hot water per minute. But our testings and feedback from the owners show that the real maximum flow rate is about 5.6 GPM in the warmer climates. If you live in the colder climates where the groundwater temperature is as low as ~42°F, you should expect no more than 3-3.5 GPM.

At 5+ GPM this whole house electric tankless water heater can easily handle 3 showers running simultaneously. If you live in the northern states, it’ll heat the water for 1 shower and some additional faucets running simultaneously. If you need more, check out the ECO 36 model which can handle up to 7.5-8 GPM.

Ecosmart ECO 27 kW draws 113 amps at full load. Which means you would need to have at least 150 amp service. Also, make sure you have enough place for 3 double poles 40 amp breakers in your panel.

Overall, it’s a great whole house electric tankless water heater and we definitely recommend it.

2. Stiebel Eltron Tempra 24 Plus Whole House Electric Tankless Water Heater

Stiebel Eltron Tempra 24 Plus Whole House Electric Tankless Water Heater
Stiebel Eltron Tempra 24 Plus Whole House Electric Tankless Water Heater:
  • Max. Flow Rate: 4.5 GPM
  • Activation Flow Rate: 0.5 GPM
  • Dimensions: 4.63 x 16.63 x 14.5 inches
  • Service Requirements: 100 amps (2 double pole 50 amp breakers)
  • 99.8 Energy efficient
Read Verified Customers Reviews
Pros
Stable temperature output
Easy to use
Small CO2 footprint
Extremely quiet
Convenient digital display
Cons
If not properly sized, may cause pressure drops

The next one on our list is Stiebel Eltron Tempra 24 Plus. This is a German brand that is well known for its advanced technology.

Stiebel Eltron Tempra 24 Plus is a whole house electric tankless water heater. It is best suitable for homes with 2 bathrooms.

One special thing about this whole house electric tankless water heater is its Advanced Flow Control™ technology. It makes sure that when the hot water demand is higher than the unit can typically handle, it prevents shower or the appliances to get cold water by reducing the pressure and keeping the water hot.

It means that you may get less hot water but it wouldn’t be colder as it sometimes happens with other tankless water heaters.

Now, let’s get to the technicals.

It’s a bit less powerful than the Ecosmart ECO 27. According to the technical specifications of the unit, it’s able to provide 1.5 to 4.5 GPM of hot water depending on the temperature rise. That’s enough to supply 2 showers running at the same time without pressure drops or temperature fluctuations.

But you can also pick a more powerful Stiebel Eltron Tempra 29 kW or even 36 kW unit if this one doesn’t fit your requirements.

Stiebel Eltron Tempra 24 Plus draws 100 amps and requires 2 double pole 50 amp breakers. One breaker with 2 live wires and a ground. And the other breaker with 2 live wires. No neutral wire is needed. Make sure you have enough space in the panel.

Owners report that the unit is extremely quiet. Silent in fact.

It also saves you huge amount of space compared to traditional storage water heaters.

We would recommend you to buy this whole house electric tankless water heater for a 1 or 2 bathroom home. apartment, or condo.

3. Rheem RTEX-24 Whole House Electric Tankless Water Heater

Rheem RTEX-24 Whole House Electric Tankless Water Heater
Rheem RTEX-24 Whole House Electric Tankless Water Heater:
  • Max. Flow Rate: 5.7 GPM
  • Activation Flow Rate: 0.3 GPM
  • Dimensions: 4 x 18 x 19 inches
  • Service Requirements: 112 amps (3 double pole 40 amp breakers)
  • Can replace a 40 gallon storage tank water heater
Read Verified Customers Reviews
Pros
Very accurate digital controller
Saves space
Unlimited hot water
American brand
Cons
Takes about 10-15 seconds before to get full hot

Rheem is a well known American water heaters brand. You may have seen it in our list of the best tankless water heaters reviews. But those were natural gas models and this time it’s an electric one.

Rheem offers several models of electric tankless water heaters of different sizes. Rheem 240V RTEX-24 is the second largest model following the RTEX-36. They both can be used as whole house tankless water heaters.

Depending on the temperature rise, Rheem RTEX-24’s flow rate ranges from 1.5 GPM to up to 5.7 GPM. Making it a perfect choice for a household with lighter hot water demand. If you have three or fewer people at your place, RTEX-24 would e a good fit.

Rheem RTEX-24 draws 100 amps. It has three heating chambers so you would need 3 double pole 40 amp breakers. I imagine you should have at least 150 amp service to be able to safely run this whole house electric tankless water heater.

If you’re living in a warmer climate, Rheem RTEX-25 is an OK tankless equivalent ro replace a 50 gallon water heater.

If you’re sure about the sizing, we definitely recommend this model.

4. Bosch Tronic WH27 6000C Whole House Electric Tankless Water Heater

Bosch Tronic WH27 6000C Whole House Electric Tankless Water Heater:
  • Max. Flow Rate: 3.5 GPM
  • Activation Flow Rate: 0.8 GPM
  • Dimensions: 15.5 x 4.5 x 12.5 inches
  • Service Requirements: 112 amps at full load (3 double pole 40 amp breakers)
  • 97% efficiency
Read Verified Customers Reviews
Pros
Reliable brand
Compact sizes
Excellent customer service
Cons
High activation flow rate

Bosch is positioning this model as a whole house electric tankless water heater but at the same time they say it’s best suited for smaller households, office suites, and garage apartments. Meaning that you shouldn’t use it for more than 1 or 2 applications at a time.

The flow rate of the Bosch Tronic 6000 C ranges from 2 GPM to 3.5 GPM. Which is lower than that in the previous models. It requires 3 douple pole 40 amp breakers and may draw up to 120 amps at full load. Although that’s almost never the case.

The activation flow rate here is at 0.8 GPM. In real life it means that if you half open the tap, Bosch wouldn’t ignite and run and you’ll get cold water from your tap. To get it work and heat the water you’re going to need to run it full open.

The average showerhead flow rate is at ~2 GPM so you probably won’t have that experience in the shower.

We’d say that Bosch Tronic 6000 C is an OK whole house tankless water heater if you’re living in a smaller household of 2 or 3 people and the hot water demand isn’t very high.

5. Eemax EEM24036 36 kW Whole House Electric Tankless Water Heater

Eemax EEM24036 36 kW Whole House Electric Tankless Water Heater:
  • Max. Flow Rate: 8 GPM
  • Activation Flow Rate: 0.3 GPM
  • Dimensions: 17.5 x 21 x 3.75 inches
  • Service Requirements: 150 amps at full load (4 double pole 40 amp breakers)
  • 99.8% efficiency
Read Verified Customers Reviews
Pros
Compact design
Extremely powerful and efficient
Simple installation
Silent work
Cons
Requires a lot of space in the service panel

If you look closely and compare Eemax and Ecosmart electric tankless water heaters, you’ll notice there’s something similar about them. In fact, they look almost identical!

You’re not wrong! Eemax and Ecosmart are practically the same company. Eemax has acquired the Ecosmart in 2013 and they’ve been working as one company since then, sharing the design and the technologies. But nevertheless, they operate as different companies and their products have some differences too.

Eemax EEM24036 is a 36kW whole house electric tankless water heater that can provide hot water for your entire home. With the flow rate of up to 8 GPM, this is the most powerful unit on our list. It should be able to easily provide enough hot water to supply a three bathroom house with 2-3 showers running at a time. If you have a tub, this unit will also do the job.

If you’re interested in more powerful whole house electric tankless water heaters, check out Ecosmart 36kW and Stiebel Eltron Tempra 36 which both show similar or better performance.

But you should also be aware of its electrical service requirements. On the inside Eemax has 4 heating chambers 9kW each. You should be able to allocate 4 double pole 40 AMPS breakers to safely run this tankless water heater.

Please, double check the service capacity before buying it. If you have less than 200 amp service, contact your electrician and ask him/her about it.

If you are 100% sure your service can handle this whole house electric tankless water heater, you won’t be disappointed. We definitely recommend you purchase this unit.

6. Black and Decker 27 kW Whole House Electric Tankless Water Heater

Eemax EEM24036 36 kW Whole House Electric Tankless Water Heater:
  • Max. Flow Rate: 5.3 GPM
  • Activation Flow Rate: 0.5 GPM
  • Dimensions: 17.13 x 4.53 x 14.76 Inches
  • Service Requirements: 112.5 amps at full load (3 double pole 40 amp breakers)
  • WARRANTY: 7-yr leakage free, 5-yr heat exchanger, 2-yr parts
Read Verified Customers Reviews

The last one on our list is Black and Decker 27 kW whole house electric tankless water heater.

Black and Decker tankless water heaters are not as popular as the previous models, but its popularity is growing thanks to the quality service and excellent performance of the brand’s products.

This on demand electric water heater offers some of the best performance for the price. According to the specifications, in the colder climates, it can provide about 3.3 GPM. In the southern states, however, it’s able to provide up to 5.3 GPM of hot water which is on par with other brands and models of the same size.

That’s enough to supply a 2 bathroom house with 2 showers running at the same time.

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