Best Electric Tankless Water Heater 2022- For Small & Medium Family

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So you want the best electric tankless water heater which doesn’t fail after a couple of months. Which offers more than 90% thermal and electrical efficiency.

Which can provide 3 to 4 hot showers without running out of water, and 3 to 8 gallons per minute (GPM) for a normal-sized family while automatically adjusting the flow of water is not a big deal.

I know you don’t want an electric unit whose maintenance, plumbing, and installation cost is more than its original price.

You also need a water heater that doesn’t take up a lot of storage space, and operates without making any noise, right?

Apart from these issues, people also face malfunctioning, warranty, and electrical problems.

After surfing through the internet, and visiting several cold areas where people are using such electric tankless water heaters, we have gathered so much information.

We have compiled all that data and results into our list of the top 9 best electrical tankless water heaters of 2021.

Each product is filtered based on energy usage, bill saving, durability, weight and dimensions, the capacity to provide hot water in high demand, and price tag.

Before getting on to the list, check our top 3 picks if you want our expert opinion.

EXPERTS RECOMMENDATION

Ecosmart ECO 36 (36kw) 240V Electric Tankless Water Heater Review
Ecosmart ECO 36
  • 99% Efficiency.
  • Good for Northern Areas.
  • Lifetime warranty.
StiebeTempra 36 Plus Reivew
Stiebel Tempra 36
  • 99% Efficiency.
  • 4 hot showers & 1 sink.
  • 3.7 GPM
Rheem 240V 4 Heating Chambers RTEX-36 Residential Tankless Water Heater Review
Rheem 240V RTEX-36
  • 8.8 GPM when needed.
  • 99.8% Efficiency.
  • Robust and Durable.

Best Electric Tankless Water Heater of 2021

As per our expert opinion, the best electric tankless water heater is one that saves the hot water portion of the electric bill while operating at 99% efficiency.

That heater shouldn’t need or require any batteries, must be compact and lightweight. It should provide a continuous flow of hot water without cold water fluctuations in between.

If there is no way you can install the unit by yourself due to complex wiring and plumbing, I wouldn’t suggest getting that heater because installation and pluming costs can bankrupt you.

Best electric water heater’s installation should be DIY, or less expensive if we are calling a professional.

Water temperature is high in most southern states like Florida, Texas, and California. Electric Tankless units will operate at optimum efficiency where groundwater temperature is higher.

#1 .Stiebel Eltron Tempra Plus 36 KW –Best Electric Tankless Water Heater for Whole House

Stiebel Eltron Tempra 36

HIGHLIGHTED FEATURES

  • 15-20% savings from the hot portion of the electric bill
  • Operates at 99% energy efficiency.
  • 3.7 Gallons of hot water per minute (GPM).
  • 0.77 GPM minimum flow required to activate the unit.
  • 86 TO 140 degrees Fahrenheit output water temperature range.
  • Does not require venting parts.
  • Less expensive to install compared to gas tankless water heaters.
  • Advanced flow control.
  • 3 x 50 A DP min: required breakers.

For a non-tank type heater, Stiebel Eltron Tempra is the leading brand in the market. Like its predecessors and other variants, Stiebel Eltron Tempra plus 36 is precisely built so that it would last for years without maintenance.

The best electric tankless water heater for the whole house. A large house usually requires multiple showers a day. It is not all about showers, bigger homes need more hot water for daily life use like doing dishes, washing hands, etc.

Largest heating module in the Stiebel Tempra Plus series:

There is a reason Steibel plus 36 is considered the best-rated electric tankless water heater for bigger homes. It works on 3 heating modules to provide enough hot water to the farthest of the corners of your home.

The reason I was talking about is when there is less demand like only one shower is operating, then the number of heating modules at work will be only one. It means no extra electricity will be used to power up all three heating modules.

Gallons per minute and the temperature range:                                                                                                                                                                                                                                                             

You will get 3.7 to 4 GPM (gallons per minute) consistently where water (input) drops to 43 degrees Fahrenheit. That is more than enough to run 2 hot showers and a sink for the whole day.

But wait,

Stiebel Eltron Tempra plus 36 was advertised to give you four hot showers and a sink on 72-degree inlet temperature, and after considering many positive reviews from the buyers, we believe this unit has fulfilled its promise.

Generating up to 7.5 GPM using 72-degree inlet temperature, four hot showers and sink is always on.

Output ranges from 86 to 140 degrees Fahrenheit. I like to take bath with sizzling hot water. Depends on you.

Efficiency:

Stiebel Eltron Tempra plus 36 is considered the best electric tankless water heater for its flawless efficiency too. This unit works at 99% efficiency which means it will not waste energy to produce hot water.

Tempra plus 36 will save 15-20% from your bill. Install the low flow showerhead and sinks to conserve water and energy, the energy savings can be higher. Some homeowners have reported that.

This unit uses futuristic microprocessor technology that allows the user to monitor and control the temperature at will.

A common problem with tank-type water heaters or with other tankless units is the fluctuation of temperature during the bath.

Suppose you are enjoying a hot shower and suddenly there is a flow of cold water in between. It’s a real pain in the ass. Tempra plus 36 has a self-modulating feature that helps to maintain a steady temperature while preventing fluctuations.

Size and convenience:

Stiebel Tempra plus 36 is about the size of a briefcase so you won’t need a lot of space for this unit.

It’s compact, completely silent when at work (you will not hear it working), and it can be installed anywhere.

The sturdy steel-coated body makes it a good choice for residential or commercial buildings. I find it suitable for both, to be honest.

Some very important details:

  • The minimum breaker requirement is 3 x 50 A DP (double-pole) on 300A minimum electric household service.
  • Many homeowners might need to upgrade their home service.
  • Calling a professional electrician might be costly, but it ensures a safe installation without bugs.
  • While using hard water (water in which mineral content is high), the buildup can occur causing the pipes to clog up and quit working.
  • Warranty will cover the cost, but it is safe to install a water filter.

SPECIFICATIONS

  • Weight: 19 pounds
  • Dimensions: (H x W x D): 14.52 x 16.54 x 4.61 inches.
  • Voltage: 240 volts to 280 volts
  • Batteries included in the package: No.
  • Batteries required: No.
  • Amperage capacity: 300 Amps
  • Warranty: 7 years for the leakage, 3 years for the parts.
  • 20% saving on the electricity bill.
  • Compact and easy to install.
  • Require less space.
  • It sends a consistent flow of water to the entire house.
  • Gives 4 hot showers and 1 sink when needed.
  • Highly durable under high demand.
  • In less demand, it will use less energy to operate.
  • Automatically adjust the flow of water to eliminate fluctuations.
  • Best electric tankless water heater for large families.
  • A bit expensive.
  • Requires 3 x 50A DP.
  • The homeowner might need to upgrade the home’s service.

Note: cold water inlet has a filter screen, but install your separate water filter to avoid any trouble

With 99% efficiency, compact design, and the fact that from all three heating modules, only 1 or 2 would work when there is less demand, Tempra plus 36 is on the top of your best electric tankless water heater list.

Though it is a bit pricy than your normal water heater, the quality, quantity of hot water, and durability of the product is great.

90% of customer feedback is positive. For a large, Tempra plus 36 should be considered.

I am not saying you should use it in place with temperatures below the freezing point. In a slightly warmer climate, Stiebel products are elite.

Opt for it.


#2. Stiebel Eltron Tempra Plus 24 KW

Stiebel-Eltron-Tankless-Water-Heater-Tempra-24-Plus

HIGHLIGHTED FEATURES

  • 15-20% savings from the hot portion of the electric bill
  • Operates at 99% energy efficiency
  • 2.7 to 3.1 Gallons of hot water per minute (GPM)
  • 0.50 GPM minimum flow required to activate the unit
  • 86 TO 140 degrees Fahrenheit output water temperature range.
  • Does not require venting parts
  • Less expensive to install compared to Tempra plus 36
  • Advanced flow control
  • 2 x 50 A DP min: required breakers
  • Best electric tankless water heater for normal size family

These German engineered electric water heaters are top-notch in efficiency and working. Producing around 2.7 to 3.1 GPM while automatically adjusting itself to meet the demand is awesome.

The new Tempra plus 24 model has some changes on the outside but the inside is kind of the same. All the changes made are for the better. The external body and function are cleaner now.

Stiebel Tempra 24 is 100% made in Germany. The built quality is extremely nice. For an average house that is usually 1500-1800 sq. feet, 24 KW unit is ideal if the input is 240 volts.

What does advanced flow control mean?

When the demand is greater than the unit can handle, advanced flow control automatically decreases the flow of hot water instead of shutting down and supplying cold water. Though it sends less water, the flow will be consistent.

Details:

  • At times when demand is higher, the unit can provide two hot showers and one sink.
  • It can even reach 3 hot showers with no sink at 72 degrees
  • Using the low-flow showerheads and sink aerators can get you higher levels of energy saving. More than 20%.
  • It all depends on the quality of showers and sinks.
  • Tempra plus 24 is like a silent assassin. It doesn’t make any sound while working even in high demand.
  • This electric water heater is sleek and compact in design. It can fit anywhere you want, but I would suggest installing it close to the point of delivery.
  • Like other Stiebel models, it does not require any ventilation.
  • I feel good while reviewing Stiebel water heater because I know how durable, efficient, and good they are.
  • Though they are a bit pricy and you may end up paying some extra money for the installation, but compared to other tankless models, this unit is perfect for a normal house.
  • There are two heating modules inside which is fine considering it uses less energy to operate.

Some important points I would like to mention:

  • There are some complaints about it not providing enough hot water to the entire house in colder climates (freezing temperatures).
  • This is due to that advanced flow control which limits the flow of water when the demand is high. I don’t think it is a bad thing to limit the water flow in greater demand. Less hot water is better than cold water.
  • I heard a few complaints about it taking 60-90 seconds to reach the faucet or shower, even when the electric water heater is close by.
  • Maybe there is something wrong with the installation, or the pipes have been clogged. Using a water filter is always recommended when hard water (water with a higher amount of minerals) is being used in showers and sinks.

SPECIFICATIONS

  • Weight: 16.1 pounds
  • Dimensions: 21.7 x 20.1 x 9.6 inches.
  • Voltage: 208 or 240 volts
  • Batteries included in the package: No.
  • Batteries required: No.
  • Max: Amperage Draw: 100 A
  • Warranty: 7 years for the leakage, 3 years for the parts.
  • Wattage: 18000
  • Excellent workmanship. 100% made in Germany
  • Constant temperature is maintained using an advanced flow control feature
  • Quiet at work.
  • 15-20% savings which is cool.
  • 99% true efficiency.
  • It rarely needs maintenance.
  • It will consume less electricity in less demand
  • 2 hot showers and 1 sink, or 3 showers are always on in greater demand.
  • 7-year Leakage, and 3 years parts warranties.
  • Pricier than your normal electric water heater.

It is hard for me to find any weakness in Stiebel Eltron Tempra plus 24 KW. Almost 99% of the reviewers are happy with its performance, and efficiency.

Stiebel’s advanced flow control feature is exclusive to their models only. The consistent supply of hot water even under high demand is awesome.

3.1 GPM is always on if the groundwater is about 52 degrees Fahrenheit. When reviewers state that Tempra plus 24 produces adequate hot water without fluctuating, it is the absolute truth. I have not seen anyone complaining about it.

With proper care, water filter installed, Stiebel Eltron Tempra Plus 24 KW can run for 10-15 years.


#3 .Stiebel Eltron Tempra Plus 29 KW

Stiebel Eltron Tempra 36

HIGHLIGHTED FEATURES

  • 15-20% savings from the hot portion of the electric bill
  • Operates at 99% energy efficiency
  • 3GPM, 4GPM & 5 GPM on 40, 55 & 65 degrees Fahrenheit respectively.
  • 0.77 GPM minimum flow required to activate the unit
  • 86 TO 140 degrees Fahrenheit output water temperature range.
  • Does not require venting parts
  • Less expensive to install compared to gas tankless water heaters
  • Advanced flow control
  • 3 x 40 A DP min: required breakers
  • Min: electric household electric service: 200A

The second-highest capacity holder electric tankless water heater in the Tempra series, Steibel plus 29 is a 100% German-built water heater.

A perfect choice for the houses bigger for Tempra plus 24 and smaller for Tempra plus 36.

Important details:

  • Whenever the inlet temperature drops to 40 degrees Fahrenheit, this unit can generate 3GPM in high demand.
  • At 52 degrees, two hot showers and a sink are ON.
  • At 62 degrees, 3 hot showers.
  • At 72 degrees, 4 hot showers.

The above-mentioned details are true. Tempra plus 29 is capable of producing such hot water while consuming less electricity.

Premium features:

  • Like other variants, Tempra plus 29 will also save15 to 20% on the hot water portion of the bill.
  • Advanced microprocessor technology will give that same temperature every time whenever the hot water faucet is open.
  • Endless hot water is ensured by the use of a microprocessor. It works like a sensor that continuously monitors temperature.

No venting:

Though gas tankless water heaters are so good, you need to take care of proper venting. The emission of volatile organic compounds and gases after the combustion can be dangerous if the venting is not maintained like it has to be.

Unlike the gas-fired tankless, Stiebel’s Tempra 29 doesn’t need any venting to operate. So you can use your basement or kitchen to install it without worrying about combustible gases.

Requirements:

3 separate 40 amp breakers with 8 gauge copper wiring, and min: 200 amp total service to the residence.

Efficiency:

Tempra plus 29 also promises to give 99% efficiency. It has fulfilled that promise so far.

If the temperature is above 52 degrees Fahrenheit, this unit works like a horse. It’ll give your multiple hot showers, a dishwasher/sink, or a washing machine.

In a colder environment (below 4 degrees Fahrenheit), it is usable for a single appliance at a time.

Don’t overburden it. It may give hot water to multiple appliances in colder weather with the help of an advanced flow control feature, but it is a machine. Putting too much pressure might surface some issues.

SPECIFICATIONS

  • Weight: 17.4 pounds
  • Dimensions: 6.63 x 16.61 x 14.5 inches.
  • Voltage: 208 or 240 volts
  • Batteries included in the package: No.
  • Batteries required: No.
  • Wattage: 28.8 KW
  • Max: Amperage draw: 120 Amps
  • Warranty: 7 years for the leakage, 3 years for the parts.
  • Better for normal to large families
  • 99% energy efficient
  • It has more capacity than Tempra plus 24
  • Can go beyond its warranty years if properly cared
  • Energy-saving can be greater if the hot showerheads and other appliances are efficient.
  • Quiet at work.
  • Compact design. Install it anywhere you want.
  • Pricier than Stiebel Tempra plus 24

Stiebel Tempra plus 29 is in between Tempra 24 and 36. This unit is ideal for normal to large families. You will get an endless supply of hot water even in the greater demand.

The advanced flow control does help to supply endless hot water, and the flow will be controlled to prevent cold water fluctuations.

It is pain in the ass if when 3-4 hot showers are running and the water heater starts to send cold water due to overburden. Not with Tempra plus 29.


#4 . Ecosmart ECO 36 (36kw) 240V Electric Tankless Water Heater

Ecosmart ECO 36

HIGHLIGHTED FEATURES

  • Cut the hot water portion of the bill in half (almost)
  • Operates at 99% efficiency
  • Close to 6 GPM tankless system
  • 0.3 GPM minimum flow required to activate the unit
  • Excellent for northern parts.
  • 80 TO 140 degrees Fahrenheit output water temperature range.
  • Does not require venting parts
  • 4 hot showers and 2 sinks without running out of water.
  • Digital temperature control
  • At least 200A total home service

Before shipping the Ecosmart ECO products, manufacturers test them so there might be residual water in there. It has a nice clean assembly and nice workmanship on the pipes.

Ecosmart ECO 36 is the most powerful unit of the series, with a capacity to handle the hot water needs of a large family without even running out of hot water.

Eco 36 has a self-modulating technology that monitors energy usage based on how much hot water is needed.

This unit plugs directly into the electrical system. Does not require batteries.

The overall design is beautiful and sleek. The knob beneath the screen lets you change the water temperature by 1 degree at a time.

The body:

The body and components are made from copper and stainless steel for durability, optimum performance, and quick replacement. That is why this unit is on our best electric tankless water heater list.

Important details:

  • This unit is 90% smaller than the usual water heater. It can fit virtually anywhere you want.
  • Ecosmart ECO 36 is capable of supplying 3.5 GPM at low temperatures without fluctuations.
  • To make it easy: It can maintain two hot showers without running out of water.
  • If your demand is greater like four showers at a time, no problem. You will get four hot showers simultaneously, but the unit will automatically adjust the flow (low flow rate) to prevent cold water fluctuations in between (cold water will not disturb you amid the bath).
  • It can also produce 6 gallons per minute: 4 hot showers and a sink.
  • This unit requires 150 AMPS dedicated.
  • Required wire: 4 x 8 AWG.

Efficiency:

This tankless electric water heater delivers over 99.8% efficiency. The hot water portion of the bill is almost cut in half (true capacity).

The patented self-modulating system automatically adjusts the energy consumption depending on the amount of hot water required by the user.

It means: If the hot water requirement is less, the unit will consume less energy to operate.

Warranty:

A limited lifetime warranty is offered by the Ecosmart ECO 36. It is a long-term investment for your home. It helps to cut the additional maintenance.

SPECIFICATIONS

  • Weight: 18.35 pounds
  • Dimensions: 3.6 x 21 x 17 inches.
  • Voltage: 240 volts
  • Wattage: 36000 watts.
  • Batteries included in the package: No.
  • Batteries required: No.
  • Amperage capacity: 150 Amps
  • Warranty: Limited Lifetime Warranty
  • 99.8% energy efficient
  • Significantly cut the hot water portion of the bill
  • Lifetime warranty offered
  • Self-modulating system that adjusts the temperature
  • Super easy installation
  • Endless hot water (true)
  • Celsius to Fahrenheit converter on the screen
  • Excellent for colder weather (below 40 degrees Fahrenheit)
  • Cannot adjust individual faucet temperature
  • You need a licensed technician for the installation otherwise, the warranty will be void.

Ecosmart ECO 36 is an efficient, budget-friendly, highly durable, and trustworthy water heater. This unit is portable, easy to install, and built to supply a great deal of hot water to big homes.

The temperature knob is easy to use. There is not much science in it. It is built precisely to last for years. That is why manufacturers are giving a limited lifetime warranty.

I would suggest installing a 300 amp service or above. Though it is an excellent unit, for most homes, a 200 amp service can cause light flickering. Haven’t heard too many complaints about it, but be safe than sorry.


#5 . Ecosmart ECO 27 (27kw) 240V

EcoSmart ECO 27

HIGHLIGHTED FEATURES

  • Cut the hot water portion of the bill in half (almost)
  • Operates at 99% efficiency
  • Close to 3 GPM at 37 Degrees F inlet temperature
  • 6 GPM when the inlet temperature is greater.
  • Activation flow: 0.3 GPM
  • Excellent for northern parts.
  • 80 TO 140 degree Fahrenheit output water temperature range.
  • Does not require venting parts
  • 4 hot showers and 2 sinks without running out of water.
  • Digital temperature control
  • Field replaceable elements.

Ecosmart ECO 27 is the most popular and positively reviewed, top rated  tankless electric water heater in the market. Ideal & budget-friendly choice for medium size family (3-5 people) in northern parts where temperature can drop below 37 degrees Fahrenheit.

It works on 3 heating modules. It can provide 5.6 to 6 GPM in warm weather.

Note: Ecosmart ECO 27 does not provide instant hot water, but endless hot water. It takes about 10-12 seconds to warm the water.

The requirement for installation:

This unit requires three 40 amps pole breakers. If you need to upgrade your service to three 40 amps, you might end up paying a lot.

If you do it yourself, you avoid the lifetime limited warranty, otherwise, a licensed technician can set you back two-three thousand dollars.

Hot water supply:

When the unit is running properly, 4 hot showers and a sink without running out of hot water.

Space:

Compared to massive tank water heaters, Ecosmart ECO 27 is sleek, compact, wall-mounted. It is 90% smaller than a tank.

Efficiency:

Almost 50% savings on the hot water portion of the bill according to the department of energy.

Heating modules will consume less energy if the demand is low. This is not just a statement, it truly does.

Inside of the Ecosmart ECO 27 heater:

Internal components are made from copper and stainless steel for optimum performance, durability, and easy replacement. We know copper is a good heat and electricity conductor, it has excellent corrosion resistivity and strength.

Important points

  • This unit is exclusively made for colder climates.
  • Though it adjusts the flow of hot water in high demand to prevent cold water flow, the overall water flow is decent.
  • Required wire: 3 set 8 AWG.
  • Pipe fitting: ¾†NPT.
  • The warranty covers the cost of the heater; does not cover labor cost.

SPECIFICATIONS

  • Weight: 10.98 pounds
  • Dimensions: 3.63 x 17 x 17 inches.
  • Voltage: 240 volts
  • Wattage: 27000 watts.
  • Batteries included in the package: No.
  • Batteries required: No.
  • Amperage capacity: 112.50 Amps
  • Warranty: Limited Lifetime Warranty
  • Temperature can be adjusted in 1-degree adjustment
  • Highly efficient in greater demand
  • 99.8% actual efficiency.
  • For hot showers and a sink is always ON in greater demand.
  • Budget-friendly in the home electrical service is already set.
  • Endless hot water
  • Not venting required
  • Consumes less energy if the demand is very low.
  • Homeowners with no electrical experience end up paying some bucks. They usually call professionals.

For anyone with a high demand for hot showers, sinks, and appliances, Ecosmart ECO 27 is the ideal choice at a fair price. This unit is durable and reliable in greater demand. Many of my friends are using it, and they haven’t complained about its performance.

People with DIY plumbing or electrical knowledge and at advantage, but you might end up paying a lot if you don’t know how DIY.

You must call a licensed professional for the installation, otherwise, the warranty is avoid.


#6 . Rheem RTEX-18 18kW 240V Electric Tankless Water Heater

Rheem RTEX-18 240V

HIGHLIGHTED FEATURES

  • Savings on the energy bill
  • Operates at 99.8% energy efficiency
  • 4.4 GPM depending on the inlet temperature
  • Does not require venting parts
  • Less expensive to install compared to other tankless models.
  • Advanced self-modulation
  • Two heating elements
  • Two circuit breakers are needed.

I will try to be as precise and accurate as possible because most of the reviews online on this model are very misleading. A clear idea of the inlet and outlet water temperature is necessary.

Rheem RTEX-18 has two heater elements. Both are replaceable if one burns out for any reason. It requires two circuit breakers.

Lower Rheem models have 1 heating element that requires 1 circuit breaker, and upper models with more heater elements thus, requiring more circuit breakers.

Check out how to replace the water heater element in case you mess things up

Amperage:

A 100 amp breaker box will not run this unit. This unit pulls 72 to 80 amps.  So if you have anything else running like Air-conditioning, heater, you’re gonna be tripping breaker, your lights gonna be flickering, so on so forth.

A 200 amps breaker box is needed for this electric water heater.

 Inlet and outlet water temperature test for Rheem RTEX-18

Insert a digital thermometer into a glass, and run the faucet. If the inlet temperature is about 40 to 43 degrees Fahrenheit, the outlet hot water temperature after turning on the water heater will be around 130 to 140 degrees Fahrenheit (after manually setting the temperature to 140 degrees).

Efficiency:

With digital temperature control, you can set the temperature in increments of 1 degree FAHRENHEIT. Temperature ranges from 80 to 140 degrees Fahrenheit.

A couple of hot showers, a sink, and a dishwasher is very much getable depending on the inlet temperature.

SPECIFICATIONS

  • Weight: 14.8 pounds
  • Dimensions: 18.25 x 3.5 x 14.5 inches.
  • Voltage: 240 volts
  • Batteries included in the package: No.
  • Batteries required: No.
  • Wattage: 18000
  • Water consumption: 7 gallons
  • Warranty: 5 years
  • 99.8% energy efficient (true)
  • Works like a horse if inlet temperatures are between 40 to 50 degrees Fahrenheit
  • Twin copper made heating elements.
  • Endless hot water supply
  • Two hot showers in less demand. 3 hot showers in greater demand.
  • Compact and cool-looking design.
  • Heating elements are easily replaceable.
  • Without 200 amp service, you will tripping breakers.

Rheem RTEX-18 is popular among people living in cold areas that is why it is on our best tankless electric water heater list.

Its efficiency, durability, ability to supply endless hot water in greater demand, continuous hot water supply without cold water supply in between is real.

This unit does possess the above-mentioned features. I am recommending Rheem RTEX-18 for a medium-size family.


#7. Rheem 240V 4 Heating Chambers RTEX-36 Residential

Rheem-RTEX-36

HIGHLIGHTED FEATURES

  • Savings on the energy bill
  • Operates at 99.8% energy efficiency
  • 8.8 GPM when needed (greater demand)
  • Does not require venting parts
  • Less expensive to install compared to other tankless models.
  • Advanced self-modulation
  • For a large size family

Rheem RTEX-36 is precisely designed to supply endless hot water to the entire home (2 to 3 bathrooms) at once. This unit also provides 99.8% efficiency like other Rheem models.

Hot water supply:

Rheem RTEX-36 claims that it can provide seven water-consuming devices at the same time.

Giving you a rough idea:

  • Water saver shower head: 1.5 GPM
  • Standard shower head: 2 GPM
  • Standard hand sink: 0.5 GPM
  • kitchen sink: 1 to 2 GPM
  • Dishwasher: 1 to 2 GPM
  • Washing machine: 1 to 1.5 GPM
  • Bathtub: 4 GPM

Heating modules:

Heating modules are 100% made of copper which is corrosion-free, an excellent heat conductor, and an electric conductor. Brass is also a part of its construction to make it more durable.

Other important details:

  • Digital display with Fahrenheit to Celsius converter.
  • An advanced self-modulation system increase/decrease the temperature, and flow rate of the outgoing water.
  • Though it is a bit expensive compared to other models, it is designed to supply water to large households.
  • Large enough to fill a garden tub

SPECIFICATIONS

  • Weight: 22.7 pounds
  • Dimensions: 4 x 22 x 19 inches.
  • Voltage: 240 volts
  • Amps: 150
  • Wire size: 8 AWG
  • Batteries included in the package: No.
  • Batteries required: No.
  • GPM: 8 GPM+
  • Warranty: 5 years
  • Excellent for a large household
  • Best electric tankless water heater for the whole house
  • 8.8 GPM is very much getable in greater demand.
  • Threaded for easily replacement
  • At 40 to 50 degrees F inlet Temp: 140 degrees F outgoing water.
  • Robust and durable
  • This unit won’t consume unnecessary energy to heat the water
  • Low water flow will not activate it.
  • A bit pricier.

Rheem RTEX-36 is an excellent choice for large households where 2 to 3 bathrooms run simultaneously. It won’t out of hot water under any situation. It might decrease the flow rate of hot water to meet the demand.

The heating modules and body are made of high metals like Copper and Brass. A couple of guys that I use to know are using this exact model. They say this is the best tankless electric water heater out there.  I don’t know about that, but it certainly is one of them.


#8. Eemax EEM24018 Electric Tankless Water Heater

Eemax EEM24018

HIGHLIGHTED FEATURES

  • 80 to 140 degrees F temperature ranges.
  • Compact size
  • Savings on the energy bill
  • Excellent Thermal efficiency
  • 0.3 minimum GPM to run the unit
  • Two hot showers and a sink in a colder climate.
  • Two heating elements
  • Does not require venting parts
  • Less expensive to install compared to other tankless models.
  • Advanced self-modulation

Eemax EEM24018 is a highly underrated tankless water heater. This unit has proven to be very useful to its owners. It is capable enough to supply endless hot water for two showers and a sink in a colder climate.

Eemax EEM24018 is powered by 240 volts. It is an 18KW. The design is compact, sleek, and beautiful. Home décor fans might love it indoors.

Some important detail:

  • This unit has self-modulating technology. It means Eemax EEM24018 will only heat the water when you need it and consumes energy according to the need.
  • Consistent, instant, and endless hot water is promised by the manufacturers
  • Digital temperature control in an increment of 1 degree F.
  • This water heater provides 1 hot shower and 2 sinks, or 2 hot showers and 1 sink simultaneously in a colder climate.
  •  In a warmer climate, it is very much capable of producing four hot showers.
  • In a nutshell, Eemax EEM24018 is enough for a normal size family.

Self-installation of 18 KW Eemax EEM24018:

Tools needed for the installation

  • Pencil
  • Flathead screwdriver
  • Teflon tape
  • Phillips head screwdriver
  • Tape/measure ruler
  • Needle nose Pliers
  • Adjustable Wrench
  • Pipe cutter

Note: Sizing is extremely important. Before choosing a tankless water heater, make sure your unit can provide the output you require.

Mechanical Installation:

  • Mount the unit on the wall first.
  • Connect the water source to the inlet side of the unit
  • Connect the pipe to the outlet unit of Eemax EEM24018
  • Make sure the plumbing connections are made correctly.
  • Turn on all the fixtures (faucets, sinks, etc.) of your home to purge the air from the water lines.

Electrical Installation:

  •  For this 18KW unit, two sets of 8 gauge wires are needed.
  • A ground wire.
  • First, connect the wires to your unit.
  • Then, connect the other side of your wire to the circuit breaker.
  • Two 40 amp double pole breakers are required for Eemax EEM24018
  • Don’t leave any loose ends, make sure all the wires are connected properly.
  • Set the outlet temperature on the digital display by adjusting the knob.

Finally, enjoy the hot water provided by your Eemax EEM24018 tankless electric water heater.

SPECIFICATIONS

  • Item Weight: 14.47 pounds
  • Item Dimensions: 17.00 x 14.00 x 3.75 inches
  • Voltage: 240 volts
  • Water consumption: 3.5 GPM
  • Batteries included in the package: No.
  • Batteries required: No.
  • Rate pressure: 25psi minimum, 150psi maximum.
  • Warranty: 5 years for leakages, 1 year for parts.
  • Super-efficient
  • Self-installable
  • Exclusively made for a medium-size family
  • 99.8% energy efficient
  • More than 2 showers are very much getable in greater demand
  • The internal design is neat. You can spot all the necessary equipment for self-maintenance.
  • It saves up a chunkier hot water portion of the bill.
  • It requires additional wiring.

Eemax EEM24018 is a compact water heater with a sleek, and neat design.  Probably the best electric tankless water heater in terms of easy installation.

It is on the list because of its performance, a 5-year warranty on leaks, and a 1-year warranty on parts.  The heating modules are replaceable.

I don’t think it is difficult to install this unit. Compared to other tankless water heaters, I find Eemax EEM24018 easy to operate.


#9 . Rinkmo Electric Tankless Water Heater – 24KW

Rinkmo Electric

HIGHLIGHTED FEATURES

  • Small like a suitcase
  • No inner mineral corrosion
  • Auto stops when water pressure becomes low
  • Auto-detects any faults
  • Savings: 60%
  • No high maintenance cost
  • 3 hot showers and 3 faucets in greater demand
  • Free from leakages, combustion, or explosion

Rinkmo 24kw Electric Tankless Water Heater is a hidden gem in the electric water heater market. I am more than satisfied with this delicately manufactured unit.

This unit represents a new generation of safe, efficient, durable, and cost-effective water heaters that are never seen before.

Some important details:

  • u003cstrongu003eHeating elements u003c/strongu003eand water pipes are separated from each other. There is no direct contact so the risks of corrosion, leakages, and explosions are eliminated.
  • u003cstrongu003eYou are also safe from annoying tube cleaning work u003c/strongu003eand maintenance costs almost zero courtesy u003cstrongu003eof indirect contact between water and heating elements.u003c/strongu003e
  • u003cstrongu003eIn other words, the u003c/strongu003edesign reduces the precipitation levels.
  • Your hot water portion of the bill will be reduced to u003cstrongu003ealmost 60%u003c/strongu003e which is kinda amazing. These are not just claims, 50 to 60% bill reduction is actual.
  • With u003cstrongu003e8% efficiency, Rinkmo 24kw u003c/strongu003esends hot water in just 3 seconds.
  • u003cstrongu003eEndless u003c/strongu003ehot water to the entire house.
  • Automatically adjusts the power based on the flow rate. It means no sudden temperature changes thanks to the temperature and flow sensors.
  • Minimum energy loss.
  • u003cstrongu003eHighly compact, and small u003c/strongu003ein size. Install it anywhere you want.
  • u003cstrongu003eSwitch u003c/strongu003ebetween Celsius and Fahrenheit.

Safety:

Rinkmo 24kw works on automation. When the unit detects outlet temperature is close or has reached 167 degrees F, the system will cut off the heating for safety. The water temperature will not fluctuate anymore. Rinkmo 24kw resist cold to flow amid bath.

Temperature reminder:

The display will shoot an alarm in the temperature is less than 37 F, or greater than 167 F (<37, >167).

Design:

Rinkmo 24kw has an awesome home décor design. You can install it in traditional places too like crawl space, basement, garage, attic, or utility room. Even a closet is a good option considering the chances of explosion or leakage are almost zero.

Rinkmo 24kw electric water heater for commercial places:

Rinkmo 24kw is fireproof, it is built with high-quality metal, and the machine auto stops if no water to be heated. Such features make this unit a good option for commercial places like:

  • Barbershop
  • Apartment
  • Beauty salon
  • Gym
  • Restaurant
  • Hotel etc.

ZERO mineral buildup:

  • No dirty water
  • No scaling, circuit board damage
  • Minimum to zero cleaning costs
  • No leakage or burnout risk
  • No-replace heating elements
  • Stable temperature

Important steps you need to follow before purchasing Rinkmo 24kw

  • First, determine your average inlet temperature. It will help you to understand how well your unit will perform in your area.
  • Second, calculate how many appliances you want your water heater to run simultaneously.
  • Finally, check if the unit has positive reviews from its owners in a colder climate. It will help you to understand whether you should buy it or not.

SPECIFICATIONS

  • Item Weight: 21 pounds
  • Dimensions: 20.65 x 16 x 7.5 inches.
  • Breaker: 3x40AMP
  • Cable: 2x8AWG
  • Volts: 240/208
  • Batteries included in the package: No.
  • Batteries required: No.
  • Wattage: 24KW
  • Water pipes and electricity separator
  • 37 – 167 Degrees F temperature ranges.
  • Temperature protection % LED alarm
  • Get hot water within 3s.
  • 2 hot showers, 3 faucets at the same time.
  • Excellent for small apartments to mid-size households
  • Water pipes are separated from elements to prevents explosions and corrosion
  • Cut the energy bill to 60% approximately
  • 99% energy efficient.
  • No sudden temperature jumps, or cold water amid the bath
  • An alarm is set for water T <3, T >167 degrees F.’
  • No unnecessary mineral buildup in the pipes.
  • Designed like a small suitcase (compact)
  • A bit pricy.

I stumbled upon Rinkmo 24kw while researching the best tankless electric water heater on the internet, and offline. I never knew Rinkmo models before, and I am baffled by its performance. This unit is elite at a really budget-friendly price.

I like the fact they have separated the heating coils from the water pipe. Cases of explosions and malfunctions have been reported in the past where heating elements and water are in direct contact.

Don’t worry, indirect contact doesn’t affect the thermal efficiency.

Trust my reviews, and opt for this model. You will not be disappointed.


Best Electric Tankless Water Heater Buyer’s guide

If you want the best electric tankless water heater which is not only budget-friendly, but energy-efficient, long-lasting, which supplies endless hot water without fluctuations, and which is easy to clean and maintain, then our buying is essential for you to make a purchasing decision.

Best Tankless electric water heaters are not cheap, a proper data-driven buying guide is necessary before purchasing one.

Tankless electric water heaters are quickly growing in popularity given their ability to deliver 98 to 99% thermal efficiency, endless hot water whenever required, and significant savings on the hot water portion of the bill.

Most importantly, understanding the inlet temperature of the household is essential. Based on the inlet temperature, we can determine which unit is suitable.

Most electric units in the market have poor performance when it comes to the colder climate. Before 37 degrees F, you will be disrupted by the cold water amid the bath. Temperature sensors in most units are not good enough.

Moreover,

Most electric tankless types are power drainers. Keeping in mind, a unit that saves energy and supplies endless hot water to the entire, or most of the household is the best tankless electric water heater.

Let get into the most functional and data-driven buying guide for the Best Tankless Electric Water heater.

  • Efficiency and material
  • Features with benefits
  • Design and size
  • Budget
  • Savings
  • Installation
  • GPM
  • Required outlet temperature
  • Safety
  • Maintenance cost
  • Warranty

Efficiency:

Efficiency

First and foremost, the best electric tankless water heater should be 90 to 99% energy efficient while working. No way around it. Let me explain:

  • Most models use a significant amount of electricity to heat the water.
  • We purchase a tankless electric type to save our energy bill in the first place, so what is the point if the unit is draining electricity to operate.
  • We have prepared a list of the best tankless electric water heaters with over 90% energy efficiency.

Check the thermal efficiency too. Heating elements made of good metal offer excellent thermal efficiency.

A Nichrome-based heating element/coil will offer maximum thermal and electrical conductivity.

Every season, you will be cleaning your heater due to scaling and corrosion problems, but copper is excellent in resisting corrosion. Check out the metal used in manufacturing the electric heater.

Features With Benefits:

If you are ready to spend some money on an electric water heater (usually expensive), then why not spend some extra $$ and look for a unit that provides as many features as possible.

A quality unit will offer savings on the hot water portion of the energy bill. It will operate at 99% energy efficiency while providing as many hot showers, faucets, and other appliances at the same time as possible.

The best tankless electric water heater does not require many pole breakers to operate. Many units come with an advanced flow control feature.

This feature provides stable temp: whenever required. It means, it won’t consume electricity unnecessarily, but only operates when required.

Design And Size:

The design and size of a unit are important in many ways. A good compact design is easier to troubleshoot. The electric and mechanical maintenance cost will be cheaper if the unit is easy to diagnose.

Heating elements and wiring shouldn’t be complicated to understand. Most of the electric units are very small. A normal-sized heater will save up a lot of space in our backyard or basement.

Normal tank-type heaters are humongous. It is a pain in the ass to move them around for maintenance or any other reason. But, with an electric unit, you can fit them virtually anywhere you want.

Note: Opt for compact models.

Budget:

The main reason a user opt for a tankless electric type is that it would benefit them in the longer run, and they are cheaper than most gas-type tankless units.

A tankless electric heater can be expensive too if you don’t know any electrical work. These types need up-gradation in the home electrical service, and you need a licensed professional to install the unit otherwise warranty will be void.

Though such is not the case with most units, always check the overall cost including maintenance and installation.

We have listed a lot of quality water heaters in our reviews that are budget-friendly and excellent in their operation.

Rinkmo, Ecosmart, and Rheem models are budget-friendly. All three brands are suited for colder climates where temperature can drop below 37 degrees F.

A normal tank type or gas tankless water heaters are popular in those regions, but they are expensive. Above mentioned models have proven their worth in cold regions.

Savings:

Savings

Every manufacturer points out the percentage of energy-saving offered by the unit. A conventional electric water heater is a power devourer. You may think you are conversing power, but actually, you not are saving anything.

The latest tankless electric units offer 50 to 60% savings on the hot water portion of the bill. Stiebel, Rinkmo, and Ecosmart are known for their potential energy saving.

That is why we have precisely chosen those units that are efficient in their work, and are saving a chunkier portion of the bill.

Read our reviews on each item, you get an idea of the potential energy savings.

Installation:

Installation

Installing an electric tankless unit is a completely different thing. Electric units are indeed less expensive than their gas-powered counterparts. A quality electric unit is bought for around $500 – $600.

But,

Not all homes are equipped with the electrical services that they need to operate an electric water heater.

Firstly, you must upgrade your home service to 200amps or 300 amps, whatever the requirement is.

Secondly, for most models, you will need a licensed professional to install, otherwise, the warranty will be canceled.

The process of installation is not difficult, but the process of paying money is difficult.

I have written a guide for installing an electric water heater, check it out, maybe it’ll help you save some dollars.

GPM (Flow Rate):

Flow Rate

Normally, you would want your water heater to supply enough hot water to satisfy all your needs. 3 to 8 gallons per minute for a normal size family is a standard.

If you live in a cold region and need 4 to 5 GPM, you would want to look for 6 to 7 GPM. Just be assured of having enough hot water supply. Though an electric tankless unit can supply endless hot water, sometimes a couple of extra hot showers or faucets are required.

Luckily: In addition to climate zone charts provided by the manufacturers, we have calculations that will help you to understand the flow rate of your household/apartment.

Check it out

Required Outlet Temperature:

Determining the inlet and outlet temperature is extremely important. Most of the tankless electric water heaters do not work properly in a colder climate that is why the following steps must be looked into:

  • Open all the faucets, sinks, and other appliances.
  • Run all the water to purge the air in the pipes.
  • Take a glass and a digital thermometer.
  • Pour the glass with water (normal water from the faucet)
  • Insert the digital thermometer into the glass and take the inlet temperature.
  • Let the water run while you are taking the inlet temperature.
  • 2 to 3 minutes will be enough. Now check what is the inlet temperature of your household.
  • If the temperature is between 37 to 45 degrees F, you will need a unit that can operate in colder climates like Ecosmart 36, Rinkmo, and Rheem 24.
  • Above mentioned models are excellent in colder regions. They have proven their worth.
  • If the inlet temperature is a bit warmer like above 44 to 46, Stiebel, Ecosmart, and Rheem should be chosen.u003cstrongu003e u003c/strongu003eDoesn’t matter the rated KW. Any model would do.

In addition to the temperature charts provided by the manufacturers, we got a temperature rise calculation for better understating. Check that out to understand the water temperature of your house.

Safety:

safety

Leakages, explosions, and scaling is a concern in water heaters. Particularly in electric units, we have seen many cases of explosion due to the direct contact of electricity and water.

The models listed above have the least explosion rates due to their supreme metal, and wiring quality.

Moreover,

  • Tankless units are far less prone to leakages than their predecessors (tank type).
  • Tankless units are more reliable in terms of temperature control. There are risks of scaled wounds from overheated water courtesy of tank-type heater, but electric tankless models regulate the temperature to maintain safety. So the chances of getting burned by hot water are closed to zero.
  • The risk of explosion is always there, especially if the unit is installed in the garage where fumes and explosive agents are normally found.
  • Moreover, an electric water heater needs water and electricity to work. The risk of a short circuit is maximum in the presence of water.
  • An explosion can be the result due to the huge amount of electricity involved to run the unit.

Make sure to:

  • Call a licensed professional to install the unit. He/she knows how to make wiring connections properly.
  • If there is a need for up-gradation of home electric service, you must. Most units need 200amps or 250 amps to work properly.
  • If you want to install the unit yourself, follow the guidelines step by step, and don’t be a lazy ass person.
  • One wrong move can not only burn the unit, but you will lose your opportunity to claim the warranty too.

Maintenance Cost:

The best tankless electric water heater requires minimum to zero maintenance. Most units have advanced flow control which makes deliver hot water at a temperature range that is accurate with a single degree.

These units are precisely built to minimize the risk of unnecessary burns. They help to minimize repair and maintenance costs.

The good news is,

The warranty covers most of the repair and maintenance costs. The average warranty for electric water heaters is 3 to 5 years and 3 to 4 years on parts.

Chose the unit which covers the maintenance cost, otherwise, you will be draining money from pocket if a professional is a need.

Almost all tankless electric water heaters need professionals for maintenance.

Warranty:

Warranty on leakages and parts should be preferred. We have chosen units that are offering an extensive warranty on leakages and parts.

Water heaters are a long-term investment. They will operate for more than just a couple of years.

Most of the negative reviews are based on poor installation which leads to malfunctioning. That is why those buyers face difficulties in claiming the warranty.

If you are not sure, call the professional. You may end up paying more than you may have expected, but it the beneficial in the longer run.

TOP RELATED ARTICLES

How to Troubleshoot

How to size a tankless model

Installation of electric model


Frequently Asked Questions – (FAQs)

Q: What is the best electric tankless water heater on the market?


Currently, Ecosmart, Stiebel, and Rinkmo electric tankless water heaters are top-rated models. Stiebel in particular is the leading brand in the market. It is a long-lasting water heater with an incredible water flow rate and 99% energy efficiency. 15-20% savings from the hot portion of the electric bill.


Q: Are an electric tankless water heater worth it?


Electric tankless water heaters are not only compact, lightweight, and easy to carry, but they save a significant portion of the energy bill, require less maintenance, are eco-friendly, and most importantly, they provide endless hot water. They are more than worthy.


Q: What size tankless electric water heater do I need?”

It largely depends on the size of your family, but here are some calculations:

Tankless Size to GPMFamily
3 to 6 GPM2 to 4 people
4 to 83 to 6 people
8+ GPMMore than 6 people

Q: Do electric tankless water heaters work in a cold climate?


I wouldn’t recommend a tankless electric unit in freezing temperatures, but if the groundwater temperature is between 40 to 50 degrees Fahrenheit, electric tankless might be the best choice in that case.


Q: What is the downside of a tankless water heater?


A tankless heater produces endless hot water, requires less space, a longer lifespan, almost zero leakages, and is an energy saver. The main disadvantage is the installation cost, and they won’t produce any hot water in freezing temperatures.


Q: Can a tankless water heater work for the whole house?


Yes. The Best electric tankless water heater for a Whole house can run a couple of showers, sinks, and random faucets at a time without ever running out of hot water. You will need to purchase a 4 to 8 GPM unit for a standard family.


Q: Which is a better electric or gas tankless water heater?


Gas tankless units are preferred in extreme cold, and they offer 80 to 85% efficiency, but electric tankless units are much cheaper than their relatives with 98+% working efficiency. Electric units don’t require any venting parts either.


Q: how long does it take to install an electric tankless water heater?


A licensed plumber would take 2 to 4 hours to completely install the unit, but it would take longer if you are trying to install it yourself.
Do electric tankless water heaters require venting?
No. you can even install them in your basement where there is no ventilation system.


Q: How many AMPs does an electric tankless water heater draw?


It largely depends on the model. Stiebel Eltron Tempra Plus 36 KW draws 300 amps, Tempra plus 24 draw 100 amps, Stiebel plus 29 draws 120 amps, and Ecosmart ECO 36 draws 150 amps. Many homeowners might need to upgrade the home’s electrical service.

It largely depends on the model. Stiebel Eltron Tempra Plus 36 KW draws 300 amps, Tempra plus 24 draw 100 amps, Stiebel plus 29 draws 120 amps, and Ecosmart ECO 36 draws 150 amps. Many homeowners might need to upgrade the home’s electrical service.


Q: Can you run out of hot water with a tankless water heater?


Technically, it won’t run out of hot water, but if the demand is greater than supply, it will struggle to supply water to all the water outlets. Suppose you have a unit that offers 2 hot showers, and one sink. You are using 3 showers and 2 sinks at the same time, so it won’t supply hot water to all of the devices at a time.


Q: Does an electric tankless water heater need regular maintenance?

Electric tankless units require very little maintenance. There are no venting parts or gas pipes. Though most of the models can be self-maintained, a regular inspection from a professional would be recommended because we are dealing with wires and electrical stuff.

About Fareed Nawaz

Aqua macho was started by Fareed, a renewable energy and clean environment geek who completed his degree in energy and environment in 2017. He has worked in EPA, water heater installation, and water treatment companies for 2 years before starting this website.

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