Sometimes it happens that a centralized hot water supply is absent or unavailable for various reasons (due to the high cost or impossibility of communications supplying). Then alternative sources of hot water help out and people choose the best electric tankless water heater that demonstrates all the decent features and allows you to heat the water to the required temperature in a few minutes or get almost instantaneous heat. Everything depends on the model.

The electric heater heats the water without the use of the tank. Cold water gets directly inside the unit and heats immediately. With such a tankless water heater, hot water never runs out. However, everything depends on how much water do you need. One can buy a small heater for one fixture for hand-washing. Larger models can provide water for a sink. And the largest ones are enough to get hot water for the entire house. So, before placing an order, we recommend thinking over how much hot water do you need.
Speaking about electric water heaters, they don’t require gas lines or propane coming into your house or apartment. In other words, you will save enough money to always pay bills. The water will be heated only when you need it, without fulling huge water tanks with the water and keep them hot all day long.
Pay attention that most electric heaters have a special display where the necessary parameters are set and are controlled by the management unit, adjusting the power when the pressure changes. Heater’s design and specifics of work are as follows: tap water, initially cold, heading to the tap, passes through a system of heating elements. Most modern models of the evocated water heaters are equipped with electronic control, due to which all processes are reflected on the display: hot water temperature, power of heating elements, and water flow.
If you want to make the right choice and purchase a worthwhile option, you should get acquainted with the following reviews, analyze all information, and compare pros and cons.

Electric Tankless Water Heater Reviews

Stiebel Eltron Tempra 20


The electronically controlled whole house electric tankless water heater allows precise temperature selection via the controller. This heating system with three 240V open heating elements is protected by a sealed plastic body frame (its heating capacity allows running two showers at a time). Of course, if you need hot water for one spout, one heating element will operate respectively. Be sure that you have a place in the electric panel to add three double pole breakers. The unit will heat water to a predetermined temperature using automatically controlled heating power. It is designed to work with one or more points of water intake, such as a bathtub and sink. Since the heater elements are located in a place with high humidity, the device is resistant to a high degree of calcification, which in turn serves to extend its service life. Moreover, it is suitable for soft and hard water, as it doesn’t come into the influence of scale formation.
Besides, the Stiebel Eltron is able to regulate water flow due to a “variable flow” feature. It will reduce water automatically if the output of water exceeds its capacity. For instance, if all faucets in the house give water at maximum degree simultaneously, the Stiebel will reduce water pressure for all faucets in order to keep supplying hot water.


  • It’s easy to set and regulate the water flow to have the required temperature.
  • The unit spends on average about 1.5kWh per day, and such a value is a decent result.
  • It can be easily mounted on the wall and there’s no need to make additional ventilation holes.


  • It won’t fit old houses (there’s a need to lay a power cable as the unit’s usage requires powerful electrical conduit and RCD), so the owner has to dole out money for electrical work associated with installation performing.
  • If the power goes out while you’re taking a shower, there are a few seconds of hot water left, and that’s not enough to finish the procedure.

Video Stiebel Eltron Tempra 20

Stiebel Eltron Tempra Plus 29


The Stiebel Eltron Tempra 29 Plus construction is complemented with a flask made of high-strength thermoplastic of a special design with fins and thickened walls that increases the reliability of the device. There is a display on the front panel that demonstrates the set temperature, error codes, and other operating parameters. The water is heated by two heating elements for modulation, which are scale-resistant and fully repairable. Moreover, the device itself requires three separate double 50-amp pole breakers. The 240V allows two showers to run at a time without temperature loss. It needs only 45 seconds to get hot water (from relatively warm water). The modern security system prevents the heater from starting without water supply and also automatically turns off the device in case of overheating. This unit isn’t really compact (16.5 x 4.6 x 14.5 inches), but the classic case is oriented to a wall installation with a bottom connection; therefore, it is compatible with most building layouts.


  • The Plus edition has a flow regulator that helps make sure that you have the temperature you set before.
  • There’s no necessity to make ventilation apertures (unlike while gas tank installation).
  • The built-in leakage protection is also provided.


  • In the absence of electricity, it will be impossible to get hot water (if you are taking shower and the power goes out, you have a few seconds to get out of the shower, otherwise, there will come cold water).
  • The water temperature tends to fluctuate for no reason.

Video Stiebel Eltron Tempra Plus 29

EcoSmart ECO 27


The EcoSmart ECO 27 is compact (3.6 x 17 x 17 inches) but rather powerful (27kW). It requires three double pole 40-amp breakers with a minimum of 8-gauge wire. The ECO 27 is equipped with three switches above the flow meter that bring to three copper heating elements with brass tops in order to preclude electrolysis. The circuit board with a display shows the actual temperature and appeared errors. Also, there are three chamber heat exchangers connected to three heating elements, each having an outlet thermostat to control the incoming and outcoming water temperature.
Specified unit’s use will help effectively solve the problem of hot water lacking during seasonal shutdowns or in case of force majeure. It can be easily installed and connected to a stationary mixer and is capable of producing up to 3 gallons of water per minute with temperatures up to 140°F. The adjustment is hydraulic, which means choosing the available power levels and controlling heating by changing the flow of water. A pressure sensor with support for automatic shutdown and a thermostat to protect against overheating are responsible for comfort and safety. Perhaps, this unit has a long heating period (2-3 minutes), but the EcoSmart brings unlimited hot water to the whole house, without pressure jumpings.


  • It works silently and doesn’t create even a small noise.
  • Its self-modulating flow sensor technology allows controlling energy consumption.
  • It has a digital temperature control system, so the water temperature conditions meet user expectations degree to degree.


  • The plastic control knob has some cracks.

Video EcoSmart ECO 27

Titan N-120


The Titan N-120 water heater is one of the most compact units (13.8 x 9.8 x 4.8 inches), which weighs only 7.95 pounds and is much smaller than the classic conventional water heater. It requires a 60-amp breaker and proper wire for correct functioning. The unit’s flow rate varies from 1 to 4 gallons per minute and relies upon the temp of the water. Unlike various other models, the inlet and outlet valves are placed on the unit’s sides and not on the bottom part. The temperature regulating is performed via the analog temperature controller that isn’t complemented with a number display. The power consumption of this product is 11.8kW at 240V, but the self-modulating technology allows ranging of the result, according to water discharging. It can support up to three washrooms or two bathrooms. There’s a pleasant bonus: 10 years warranty.


  • Specified water unit overheating is eliminated due to the installed protection sensor.
  • The device turns on/off automatically when opening/closing the water tap.


  • It’s recommended for the warm climate (it might be on the blink if used in cold conditions), so it can be used if the incoming water temperature is lower than 65°F.
  • It’s hard to control the water flow because the simple valve moving makes it too hot or too cold.

Video Titan N-120

EcoSmart ECO 11


Perhaps, the EcoSmart ECO 11 is regarded as the best tankless electric water heater for those users who prefer eco-friendly, compact, aesthetic, and powerful devices. It requires at least 125-amp electrical panel for mounting with 60-amp double pole breaker allied to set of 6 AWG wire. In the case of undersizing, it can become the reason for the fire. There is a power regulator for the heating elements on the front side, which allows you to select the mode of operation of the water heater and get up to 2.6 gallons per minute (for 67°F). I really like that the unit is able to handle two sinks running in-parallel or one shower. It weighs only 6.5 pounds and is one of the lightweight tankless electric water heaters. Pay attention that it can’t be hooked up directly on the shower head, the unit has to be connected to the incoming cold water pipe.


  • It frees up much of space in a small room.
  • The restrictive flow meter seamlessly performs its function.
  • It has a lifetime warranty.


  • The heat exchanger can be covered with minerals, which should be cleaned off manually.
  • Its installation requires expensive and complicated electrical works.

Video EcoSmart ECO 11

Stiebel Eltron DHC


This 120V tankless water heater is supplemented with a spiral heating element, which is made of bare wire. It needs a minimal circuit 25-amp breaker. Pay attention that the heater is completed with a flow sensor that triggers it to start heating. The Stiebel Eltron product is able to heat the water for one bathtub and one sink, no more. It requires at least a 120V power source and even can be used outdoors, as it’s protected from the weather. Another indisputable plus is the ability to work effectively even with the hard water. Such a peculiarity makes the device universal for all regions, even those ones where the lime content in water is high. It should be noted that the temperature accuracy of such a heating element allows you to adjust the temperature with the least error (comparing with a standard element). If due to the pressure decreasing in the network, the pressure of the water at its inlet reduces, the temperature of the water rises. This gives a signal to operate the thermal relay, which turns off the power of the Stiebel Eltron.


  • After setting the temperature knob on the front cover, the user can enjoy water between 86–140°F.
  • It can be placed both below and above a sink.
  • It weighs only 4.6 pounds and it is rather compact (18.9 x 7.9 x 14.2 inches) so can be placed anywhere in a room.


  • Sometimes it produces clicking sounds though the unit has to be silent.
  • You need to wait 3-4 minutes to get hot water.
  • The user gets only 3 years of the limited warranty and such a term is really short.

Rheem RTEX-13


The Rheem RTEX-13 thermostat is placed on the front side of the body frame and has a digital dial so you can set the temperature effortlessly. The unit weighs 4 pounds and is rather small (4 x 9 x 13 inches) so can be mounted everywhere. The manufacturer has added two heating elements from cooper steel, so the unit is able heating up shower and sink without problems. The RTEX-13 can function correctly only with the help of the 240V breaker and 6 AWG wire. It is resistant to scale formation and is able to operate smoothly even in conditions of constant active use. I really like that the overheating of the water heater is eliminated due to a protective thermostat.


  • The device has a high flow rate (4 gallons per minute), so it allows using both the shower and the kitchen tap simultaneously.
  • It can heat the water from 80°F to 140°F, so it’s possible even to wash the clothes.
  • There are no minimum flow requirements but the maximum is 3.17 gallons per minute that is a good bellwether.


  • It comes with no additional installation elements, the owner has to purchase everything additionally.
  • The unit produces some crackling sounds that make me nervous.

Video Rheem RTEX-13

Rheem RTEX-18


The Rheem electric tankless water heater is equipped with convenient touch buttons and an informative LED display where the setpoint temperature is reflected (varies from 80° to 140°F). Moreover, an electronic control system makes it possible to utilize a flow meter with a 0.3 gallons per minute activation point. The Rheem RTEX-18 is distinguished by its high performance for heating water that is achieved due to powerful two heating elements (coppered), which are capable of producing more than 2.54 gallons of hot water per minute (if the groundwater temperature is nearly 80°F). It works well for the whole house (with two bathrooms). Pay attention that it requires more than 240V power source and at least 2-pole breakers. At the same time, the efficiency of water heating reaches 95%. With the passage of water, the heating elements vibrate, thereby preventing the formation of scale, which significantly increases the life of the unit.


  • It requires only 13 kW at 240V to run smoothly.
  • The unit is small (4 x 15 x 19 inches) so can be placed even under a sink or in a closet.
  • It weighs only 8.5 pounds and is much lighter than heaters the same power from other manufacturers.


  • It doesn’t have the flow regulator, so it’s not really convenient to control it.
  • Sometimes it appears the E5 error denoting excessively increased flow, and all I can do is to reset the unit.

Video Rheem RTEX-18

Buyer’s Guide

How to Choose Electric Tankless Water Heater?

If you are tired of the hot water in the shower running out, then you should pay attention to the tankless water heater, a compact device that allows you to heat water immediately before being fed to the tap, without accumulation in the tank. The most popular are heaters that run on electricity due to the ease of installation and maintenance.
The main indicator that you need to build on when buying such a unit is productivity. For example, for washing hands, a flow rate of 0.79 gallons per minute is enough, to wash the dishes you need about 1.32 gallons, and taking a shower requires as much as 2.11 gallons per minute. You can also build on the necessary power, moreover, the electric tankless water heater choosing by power provides the ability to calculate the estimated electricity consumption for heating.
In addition, you need to pay attention to adjunct functions and elements presence:

  • Protection against the heating element thermal overloading.
  • Automatic deactivator when water outage.
  • Valve against a sharp pressure buildup.
  • Visual designation of the device’s activity.
  • Filter that protects the heater from plaque and sediment.

Most of the abovementioned tankless electric water heater reviews have these peculiarities and demonstrate their advantages in practice. The complete set of the unit is also important as the package must contain all the necessary pipes, fittings, plugs, shower headers, or mixers. When these parts are provided by the manufacturer, it can guarantee the high-quality installation and normal operation of the flow heater.

Is It Affordable and Can It Be Easily Installed?

It’s not a secret that the best tankless electric water heater isn’t that expensive as their gas-powered equivalents. It’s possible to purchase a decent quality unit for around $600. Meanwhile, pay attention to that some houses are built in such a way that they won’t be able to provide the heater with the electrical specifications. The endeavor to install the unit can lead to additional expenses, as the house’s electric system increasing can’t be called the cheap procedure.
One more additional bonus is that an electric tankless water heater doesn’t produce exhaust gases, so there’s no need to install the ventilation in the house. The specified device can be placed almost anywhere in the building without serious restrictions (in a room with an air temperature of at least 41℉). Pay attention that it is recommended to install special filters due to increased water hardness, as it may extend the life of the facility. You should check the water pressure in the water tap while the instantaneous water heater is turning on. In a case of low pressure, it is better not to set high heating temperature, since the device may not turn on at all.

Is It Energy-efficient and Won’t Cost Me a Fortune to Run?

Almost each the best electric tankless water heater uses nearly 98% of the electricity it receives to heat the water, so the power isn’t lost. Moreover, such units have also no losses associated with maintaining the water temperature, as in storage (tank) water heaters. For houses that consume no more than 40 gallons a day of hot water, the installation of the tankless water heater can be 24-34% more energy efficient than the storage one. You can achieve serious energy savings if you install the specified water heater at each water point, as it will heat as much water as is actually required to the temperature that is really needed.
An additional advantage is that electric tankless elements are durable. Many of them have a service life of more than 20 years, while storage ones work on average no more than 10-15 years. It doesn’t produce greenhouse gases, so the user gets hot water only via an environmental friendly way.


The undoubted advantages of the specified water heater are the following:

  • The compactness of the unit is manifested itself by the ability to place it without taking up extra space.
  • The hot water will flow in unlimited quantity and you do not need to pre-heat it, as in the storage one. Indeed, in tank water heaters, the volume of water is limited by the tank. Here, while the tap is open and the water heater is on, hot water will go.
  • Fast heating time is also a serious advantage as it requires nearly 1-2 minutes to get the required temperature water.
  • Units have an attractive appearance and are diverse in design, so they will fit aesthetically into any interior.
  • The water is not stagnated, as in storage tanks, eliminating the possibility of bacteria formation.
  • The electricity is used only when water passes through the unit, so it provides decent energy efficiency.
  • Units are equipped with protection against overheating, which, if the temperature is exceeded, sets the heating elements off and you should not be afraid of being burned by touching the facility.
  • The tankless heaters do not need to be cleaned constantly, they require minimal maintenance (compared to storage units).