Atmor Tankless Water Heater Reviews is reader-supported. As an Amazon affiliate, we earn from qualifying purchases.Learn more

Atmor is one of the leading manufacturers of electric tankless water heaters in the world.

Atmor provides economical tankless solutions for hot water delivery in kitchen sinks, full bathrooms, and even entire residential homes.

Established in 1974, Atmor has built its empire as a popular producer and distributor of electric tankless water heaters in over 40 countries.

Atmor has continuously improved its products by adopting innovative technologies. The company is very receptive of user feedback and has also improved in the area of customer service over the years.

By being aware of what the consumers want, Atmor has developed state-of-the-art products that cater to the various hot water needs of the users.

The tankless water heaters from Atmor are classified based on their applications. There are several series of units available from this brand that can be used for shower, sink, and whole-house applications.


The units have certain unique characteristics that make them different from the models of the other series. Given in the below table are the various series of electric tankless water eaters from Atmor and some of their key features.

Let us now discuss these model series in detail.

100 Series

ATMOR AT-EJSH-5 100 Series Water Heater White

The 100 series of tankless water heaters from Atmor is meant for shower applications only. These are low capacity point-of-use units that are capable of handling only one shower at a time.

All the heaters operate at a minimum flow rate of 0.4 GPM.

Atmor 100 and 100-Enjoy series are equipped with tubular heating elements that improve the efficiency of these heaters. The power rating of the models in this series varies from 2 to 9.5 kW.

The two largest units are available in models that work on a 3 phase supply.

  • These are dedicated units that ensure hot water to the showerheads without any drops in temperature
  • No long delay time for hot water
  • Must be fitted close to the shower for effective use
  • These units do not work on a 120V supply and require electrical upgrades
  • No display

120 Series

The outdated temperature setting feature of the 100 series is replaced with a stylish digital display and temperature buttons in this series.

These are high-efficiency units with a light-weight and compact body that can be fitted very close to the showerhead.

Like the 100 series, this one also has a range of units that require power supplies of 2 to 9.5 kW. These are splash-proof units with a powerful flow. The minimum flow for these units is 0.4 GPM.

  • The thermostatic design allows the users to set the temperature at exactly the temperature that they want
  • The units are small in size and weight and can be installed in any small spaces
  • Need to be installed above the showerhead
  • The units may require electrical upgrades from the current configuration

200 Series

The 200 series consists of electric tankless units that can be connected to showers, sinks, or basins in homes, offices, and other similar places.

These units have a heating element that is tubular and have four temperatures at which they can be set.

These are electronically controlled units that are capable of conserving significant amounts of energy and water. The power rating varies between 2 kW and 7 kW. The maximum available flow rate is 1.2 GPM.

  • Can be used for showers, sinks, or a combination of both
  • These are highly efficient units that help in saving money on electricity bills
  • One year warranty on all parts is available
  • The water temperature can be set at only one of the four available values

300 Series

Elegant designs and efficient operation are the specialties of this tankless water heater series from Atmor. The 300 series has units that can be used for single or multiple applications.

The units have 4 temperature settings as well as three safety indicators.

The power requirements range between 2 kW and 9.6 kW. The maximum flow rate available is 1.4 GPM. These units also feature a shower set and a self-cleaning shower head with four different shower patterns.

A Super 300 series is also available from Atmor that features digital temperature display and settings.

  • A luxurious shower set is available with these units
  • These units have some safety features that are absent in the previous series
  • These are eco-friendly products that help conserve energy and water
  • Only four temperature settings are available
  • When used for multiple applications without proper sizing, the hot water supply may not be sufficient

400 Series

This series is the successor of the 300 series and has some minor upgrades form the 300 series. The power rating is 2 kW to 9.6 kW and has four temperature settings that can be set with a knob.

The maximum available flow rate is 1.4 GPM.

An advanced version of the 400 series was released, namely, 404 series. The units have a variable power selector and a digital display to set and view the exact water temperature.

Additionally, these units have anti-scale, pressure relief and double thermostatic devices for improved safety. Power ratings vary from 5.5 kW to 8.5 kW.

Another advancement in this series is the 405 series, which has a large LCD and memory settings.

The heater allows the users to customize up to four personal temperature settings. 2 kW to 9.6 kW is the power range for this series.

  • The 404 series has advanced safety features that ensure the secure operation of the units
  • Memory settings in the heaters allow the users to customize and save their temperature settings when it comes to the 405 series
  • Apart from a few minor upgrades from the 300 series, the 400 series (initial series only) does not feature many changes

510 Series

These are eco-friendly units that are designed for single or multiple applications. These units can be used for either sinks or showers. This series is simply a higher-capacity version of the 100 series.

The temperature is set using 2 knobs. There are four available settings in this series.

The power requirements are from 2 kW to 7.7 kW. The maximum flow rate in this series is 1.2 GPM. The advanced flow control feature ensures constant temperature and flow of water.

The heating element in this series is of the tubular type.

  • Simple units with a higher flow rate than the 100 series.
  • These are eco-friendly units that comply with international standards
  • These units are economical compared to other brands
  • No display unit
  • Units with advanced features for the same flow rates are available

700 Series

The heaters under this series are highly efficient and are capable of saving up to 80% on heating bills.

The units can be used for shower or sink applications or a combination of both. The power requirement for this series is 2kW to 7.7 kW.

The maximum rated flow from this series is 1.2 GPM. These units deliver hot water immediately and require no preheating.

  • The units can be used for a variety of applications
  • These are inexpensive heaters that are compact and can be installed anywhere
  • Outdated temperature setting with knobs and no digital display is available

900 Series

Atmor 10.5kw/240v Point-Of-Use Tankless Electric Instant Water Heater Including Pressure Relief Device, AT-900-10

The 900 series is a high-performance series and has units that can be connected to multiple showers and sinks at the same time. It can be connected to the main water line to provide hot water for multiple applications.

A maximum GPM of almost 2 is available from this series. The power rating of this series is 3.5 kW to 12 kW and requires a 220V supply. The unit has four temperature settings and no temperature display.

  • The 900 series is designed for concealed installations so that it does not stand out in the house
  • If sized properly, this unit can operate multiple applications simultaneously without any drop in temperature
  • No display features and troubleshooting features are available in this series

Thermo Pro and Thermo Boost Series

18kW / 240V Electric Tankless Water Heater, 3.7 GPM, 75 Amps, ThermoPro Series with Digital Thermostatic Control

The Thermo Pro/Boost Series consists of high performance electric tankless units that are designed for multiple applications and whole-house applications.

These two series have large capacities that can be easy and economical replacements for gas units.

The Thermo Boost series consists of a modulating technology that heats the water only when required. This feature further improves the efficiency of the units and makes them more environment-friendly.

  • Energy is spent to heat water only as and when required, resulting in significant savings in heating bills
  • There are several accessories available from Atmor that accentuate the performance of these units
  • Might not meet the hot water requirements of a house if not sized properly


Atmor tankless water heaters are some of the most efficient, compact, stylish, and economical electric tankless units available in the market.

These units are perfect for point-of-use applications that are operated on relatively constant temperatures throughout the year.

If you are looking for electric tankless units for dedicated applications, we strongly recommend Atmor as these are easy to install by the users as well.

ReviewsWorthy Team

Our team consists of enthusiastic and passionate people from different fields and experience. Some are geeks and spend most of their time among gadgets while others love nature and are always on the move! We spend 10s of hours researching and writing on each topic. The articles are then quality checked by our editors. View our "About us" section for more details about process and team.

We will be happy to hear your thoughts

Leave a reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.