Best Whole House Electric Tankless Water Heaters

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. 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 and money and enjoy the luxury of endless hot water.

Anyway, you are here for the 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:

For those who want more details, we prepared several thorough reviews below. Let’s start!

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

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 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.

Here is our ultimate list of the best whole house electric tankless water heaters to buy:

1. Ecosmart ECO 27 kW

Ecosmart is a very popular and trusted electric tankless water heater brand. It offers a wide range of models with different capacities 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 tests and feedback from the owners show that the real maximum flow rate is about 5.6 GPM in warmer climates. If you live in 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 three showers running simultaneously. If you live in the northern states, it’ll heat the water for one 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. This 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

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 two 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 the shower or the appliances from getting 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 two 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 two double pole 50 amp breakers. One breaker with two live wires and a ground. And the other breaker with two 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 a 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

Rheem is a well-known American water heater 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 three double pole 40 amp breakers. I imagine you should have at least 150 amp service to be able to run this whole house electric tankless water heater safely.

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

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

4. Bosch Tronic WH27 6000C

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 three double 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 to 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

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 acquired 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 a 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 four heating chambers 9kW each. You should be able to allocate four 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

The last one on our list is the 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 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 two bathroom house with two showers running at the same time.