Electric Tankless Water Heater Reviews

Electric Tankless Water Heater Reviews article helps you to understand, find, review and select the best whole-house electric tankless appliances for domestic water heating with a supply up to 4 gpm.

Before we lead you through the detail electric tankless heater review, let us go back to the basics and present you how electric tankless water heater works.

How it works

electric tankless water heater review of titan appliancesIn order to heat the water in electric appliances, water has to pass over an electrical element. Depends on demand of hot water, you can buy a point of use like PowerStar and the whole house tank-less water heater like Tempra.

For the whole-house applications, where there is a high demand for hot water, electric tankless models are less practical as they provide less capacity, when compare to gas units.

On the other side electric models are less expensive and less complicated, making them easy to operate. Electric tankless hot water heaters are also less risky to install than gas appliances, and they involve less considerations, such as meeting the minimum supply pipe diameter.

If replacing the old storage tank type with the electric tankless unit, you have to consider the appropriate, heavier wiring. Electrical reconnection might need to be inspected by a licensed electrician.

You can use a small electric unit as a booster for remote bathrooms for example, where usage is minimal and flow rate is small.

Keep in mind that larger electric tankless models usually require 120 amps, which could overload many residential electrical panels. You should provide heavy duty wiring and according to the electrical codes properly designed circuit breaker.

When going through the electric tankless water heater reviews, it is good to know that one of the main parameters you should check is the temperature rise, which is the key element in heater's performance.

How to Select

Before buying the electric tankless water heater you should consider the next electrical requirements:

  • Amperage - as there are different requirements for amp draw from a manufacturer to the manufacturer you want to support the electrical demands of your electric water heater.

  • Circuit Breaker - it may be necessary to provide a separate circuit for your electric unit.

  • Keep in mind that there are models that support 110V, 120V, 208V, 220V, 240V, and 277V. Always check before you purchase what is the voltage you need.

Brand Reviews

For our electric tankless water heater reviews article, we have selected several popular names and models in water heating industry, covering around 24 kw of the heating power and up to 4 gpm hot water delivery:

  • PowerStar AE125

  • Stiebel Eltron Tempra 24 Plus

  • Titan SCR4 N-210

  • Eemax EX230T2T

PowerStar AE125

bosch powerstar ae125Bosch PowerStar AE125 is the whole house electric water heater that features an electronic flow switch and flow sensor to allow PowerStar to provide a constant output temperature of hot water. The electronic control PCB monitors the flow rate and the incoming water temperature by adjusting the number of heating elements required to reach the set temperature.

Each heater module is protected by an electro-mechanical thermal cut-out, to protect the unit when the temperature of any of the heater modules gets too high.

AE125 unit, with max of 22.5 KW (220V), requires 3 independent 240V AC circuits protected by 3 separate and independent 40 amp double pole breakers (US) or 1x120 Amps in Canada. Minimum recommended electrical service to the house is 200 amps. Wire size is 6 gauge in US and 2 gauge in Canada. For the 45 F temperature rise it delivers 4 gpm of hot water.

Energy efficiency is 94%. Warranty is 1 year on the unit and 10 on the heat exchanger.

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Stiebel Eltron Tempra 24

stiebel eltron tempraTempra 24 Plus from Stiebel Eltron is one of the most advanced electric tankless water heaters, equipped with the true flow modulation and thermostatic control.

Tempra doesn't work like many other electric appliances in on/off mode. Tempra implements the advanced microprocessor technology for the energy saving performance and showers without temperature fluctuation.

Tempra 24 is equipped with several flow and temperature sensors that monitor the water flow and incoming water temperature. The collected information is immediately sent to the microprocessor. Microprocessor then modulates the power by engaging the heating elements and in stages. This is the way how Stiebel Eltron electric tankless water heaters, Tempra models, are maintaining the precise output temperature of hot water.

Tempra Plus also features the advanced flow control technology that is adjusting the water flow rate to ensure that the desired output temperature is met.

To protect the unit Tempra is equipped with the thermal hi-limit cut-out switch that monitors each heating module.

Tempra 24 (24kw) requires 2 independent 240V AC circuits protected by 2 separate and independent 60 amp double pole breakers (120 Total Amps). Wiring requires minimum 2X 6 AWG copper. Minimum recommended electrical service is 200 amps.

Energy efficiency is 99%. Warranty is 3 years on the unit.


titan water heaterSCR4 N-210 Titan Tankless Water Heater features the next generation of high speed electronic integrated circuitry.

Titan provides a 10-year manufacturer's warranty against leakage on all water carrying parts, and one year on all other components.

SCR4 N-210 Titan Tankless Water Heater is resistant to mineral deposing and hard water, as it's heating elements are built from the durable incoloy (industrial-grade nickel-chromium heat-resistant alloy), housed inside rugged copper/brass chambers.

To protect the system from high temperatures, it uses a dual Microtemp thermistor with manual resettable thermostat.

With 21 kw at 240 V of the heating power, it is ideal for the whole house applications with a high hot water demand. Its energy efficiency is 99.5%.

For the installation, Titan requires 2x50 amps, each with #8 AWG wire.


reivew of the electric tankless water heaters, eemaxEemax EX230T2T, Series Three is another good quality residential electric tankless water heater for whole house application that we will review here.

Eemax EX230T2T is equipped with the high adjustable thermostat and microprocessor for the precise outlet temperature. Eemax tankless model features staged heating modules, which saves the energy as it is used for the amount of water flow that is requested. It provides up to 4 gpm of hot water.

To protect the heating element from burnout, Eemax is equipped with the high temperature limit switch and reset button. It is LEED certified.

It requires three dedicated independent 208/240V circuits and 3x40A separate and independent, double pole breakers. It provides 22.5 kw while on 240 V. 99% energy efficiency. Warranty is 1 year on parts and 5 on leaks.

Note: Always check local codes and refer to manufacturer's manual. Recommendation is to hire a licensed electrician.

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