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Home » Water Heaters » Atmor Tankless Water Heater Reviews

Atmor Tankless Water Heater Reviews

By: David Trinh
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Wherever you live and whatever your hot water needs, you can find an Atmor tankless water heater suitable for your home. As all the heaters are electric, there is no need for a gas line to install one, and any of the models will require a fraction of the space needed for a tank water heater.

Atmor produces water heaters in a range of sizes, from point-of-use heaters for a single sink up to more powerful units that may even be enough for your whole house.

Top 5 Atmor Tankless Water Heaters

  • 0.5 GPM
  • Indoor, Point of Use
  • 5.0 GPM
  • Indoor, Whole House and Point of Use
  • 0.9 GPM
  • Indoor, Point of Use
  • 1.7 GPM
  • Indoor, Point of Use
  • 2.9 GPM
  • Indoor, Point of Use

About Atmor

With just 40 years in business, Atmor is a relatively young company. Over four decades, the company has managed to develop a name for itself globally by producing eco-friendly water heaters for homes and businesses. To date, Atmor has sold more than 2 million water heaters to consumers across more than 40 countries.

All Atmor water heaters significantly reduce waste compared to tank water heaters, only heating water the moment before it is needed. They are also green in that you can recycle most of the elements in the water heater.

Cutting-edge technology at affordable prices help Atmor heaters stand apart from other tankless water heaters. Features include thermostat control, digital displays, a temperature stabilization system, and shower preference memory. This adds to the energy savings as well as improving the experience for the user.

Atmor Tankless Water Heater Reviews from Consumers Online

Most customers are satisfied with their Atmor water heaters. The main complaint is that the water heats to a lower temperature than what the user wanted. However, this tends to be a problem only when users try to gain more water than the heater is capable of producing or if they choose a heater that is unsuitable for the climate.

Installing Atmor Tankless Water Heaters

Installation of Atmor water heaters differs depending on the model. As all the heaters are electric, whichever you choose will be simpler than installing a gas water heater, as no venting is needed. Although you may have the expertise to install the water heater yourself, you must hire a licensed specialist — or you will void your warranty.

Atmor Tankless Water Heater Problems

If your Atmor water heater suffers any problems within the warranty period, you should receive any necessary repairs from a licensed electrician. After the warranty period is over, you’re free to troubleshoot on your own, provided you possess the relevant skills.

Most users find that they suffer from few issues with their Atmor water heater. The majority of problems come from choosing an inappropriate heater. It is important to choose a heater that has a higher enough GPM flow for your needs, that is suited for your number of appliances, and that works with the incoming water temperature in your area.

Issues can also occur due to power. It is important to install the water heater directly to an electrical heater; you must not install a plug to the unit. In addition, ensure that you have the right breaker size.

Finally, there are water flow problems. If flow is below the minimum 0.5 GPM, your water heater will not activate. In addition, make sure the cold water is connected to the right inlet side, as an incorrect connection will prevent water flow.

Atmor Tankless Water Heaters Warranty and Customer Service

Atmor has a department dedicated to product support and customer service. You will receive expertise from customer service advisors who work directly with the product developers. They are able to answer any questions and solve any problem. The customer support team responds to emails — there is no dedicated phone number to call.

You can also find information by reading the FAQs on the Atmor website or by downloading installation instructions and product manuals.

For all its water heaters, Atmor gives the original owner a two-year warranty on parts. This is slightly lower than average. However, you will also receive a seven-year warranty on leakage, which is significant. Liability is either the cost of the product or $1,000 — the lower of the two amounts. With written authorization from Atmor, you can return your water heater for repairs, although you will need to pay all the transportation costs.

You will void your warranty if you install or use your water heater incorrectly. This includes altering its design or having it serviced by anyone other than a professional electrician. It also includes installing or using the water heater in a way that does not match the installation instructions or any applicable laws.

Types of Atmor Water Heaters

Atmor categorizes its water heaters by suitability: whether a model is designed for just a single sink, for a single shower, as a larger point-of-use heater, or for multiple applications. Atmor further divides its water heaters into several series, which include the 900 series, the 100V series, the Enjoy series, and the two Thermo series.

900 Series

The 900 series consists of small water heaters. These are mainly for sinks, but they can provide enough hot water for a single low-flow shower in areas where incoming water temperature is high enough. The small size of the heaters make them suitable for installing under a sink or counter as well as in a cabinet.

Customers are recommended to install the 0.5 GPM sink aerator that comes with the water heater to improve performance. A licensed professional will need to carry out this task.


The AT-900-08 is a good option if you need a constant stream of hot water for a sink. It is useful if your current water heater is not powerful enough to provide water to your sink at the same time as using other appliances.

With the AT-900-08, you will receive 0.5 GPM when the temperature rise is no more than 45 degrees Fahrenheit. It is recommendable to have an incoming water temperature of at least 57 degrees Fahrenheit — anything lower than this will mean you only receive lukewarm water. This means the heater is unsuitable for homes in most northern states, although it can be ideal for homes as well as businesses like restaurants in warmer climates.

100V Series

The 100V series consists of water heaters just for showers. They are an attractive alternative to a point-of-use heater for the shower. Plus, being IP54-certified splash resistant, there is no risk of damage if you splash the heater with water from the shower.


The AT-100V-SH8 is a good option if you want to replace your current shower or if you are retrofitting a bathroom. The water heater comes with a hose, handheld shower, rise rail, and soap dish all included. It will save you needing to figure out where to install a point-of-use water heater if you have limited space in your bathroom.

To determine if the heater will provide water at a comfortable temperature and pressure, it is necessary to consider the temperature rise. For just a 35-degree Fahrenheit temperature rise, the heater will provide you with 1.7 GPM. You’ll receive just 1.2 GPM for a 45-degree Fahrenheit temperature rise and 1.0 GPM for a temperature rise of 65 degrees Fahrenheit.

You can set the thermostat to as high as 131 degrees Fahrenheit. However, you will most likely want to keep to below 110 degrees to prevent scalds and damage to the skin.

Enjoy Series

The Enjoy series is another series made up of water heaters for showers. Again, the heaters come with everything you need to create a shower and they fit on the wall in your shower enclosure or above your tub. Also like the 100V series, they are IP54-certified splash resistant.


The most popular model in the Enjoy series is the AT-EJSH-5. It is suitable for homes in warm to hot climates, especially if you are looking to install a new shower but don’t want to take power away from other appliances that also require hot water.

Offering just 0.9 GPM for a 35-degree Fahrenheit temperature rise, the AT-EJSH-5 is less powerful than the AT-100V-SH8. Plus, the flow drops to just 0.6 GPM when temperature rise is 65 degrees Fahrenheit, which may be too low for comfort for some users. However, it can reach a maximum temperature of 131 degrees, which is higher than you likely need.

Thermo Boost Series

Thermo Boost water heaters are designed to bring hot water to a single appliance as you need it. They are an affordable way to ensure you always have enough heated water. You can set the exact temperature you want in increments of 1 degree Fahrenheit and the heater will only heat the water you need.

There are two water heaters in the Thermo Boost series: a 10.5 kW model and a 14 kW model. Both are suitable as point-of-use heaters or as boosters for preheated water.


Offering 2.9 GPM, the AT-905-14TB (the 14 kW model) is ideal for a low-flow shower, washing machine, or dishwasher. It is also suitable for a regular shower or even a couple appliances in a hot climate. If you’re in a cold climate, your incoming water temperature can be as low as 35 degrees Fahrenheit and the water heater will work without a problem.

The AT-905-14TB has a different appearance than many other modern tankless water heaters — it is a gray square rather than a rectangular white box. This design could be appealing to some people, especially those who want to install their water heater in a place like the garage.

Thermo Pro Series

The Thermo Pro series has similar water heaters to those in the Thermo Boost series, although they are slightly more powerful. There are three models in the series, beginning with the 18 kW (which provides 4.0 GPM) and ending with the 27 kW (which provides 5.4 GPM).

Another difference is that the heaters in the Thermo Pro series all have self-modulating technology, which is not present in any of the economical Thermo Boost heaters. This technology means that the heaters are able to regulate how much energy they use to match the user’s hot water needs — further saving energy.


Also called the Thermo Pro 24 kW, the AT-910-24TP can work as both a point-of-use and whole-house water heater. How you are able to use it will depend on your needs and the climate where you live. The heater offers up to 5.0 GPM, which could be enough for as much as a low-flow shower, kitchen sink, bathroom sink, and washing machine all at the same time — plenty for a small home. In contrast, for a large home in a cold climate, this heater is more suited for just a few appliances and you’ll still need a second heater.

The AT-910-24TP is similar in appearance to the AT-905-14TB from the Thermo Boost series. Its narrow shape makes it easy to hide out of the way. However, you will still want easy access to the heater to change the thermostat, which requires adjusting the metal knob on the front. This is just below a digital display.

Where to Buy Atmor Water Heaters

Atmor does not sell water heaters direct through its own online store. However, you can find all the above models along with other water heaters (both those from the series mentioned and from other series) for sale on Amazon. For some models, Atmor offers the chance to order expert installation at checkout for an additional cost.

Lastly, if you still want to check out other brands before purchasing see our review here.

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David Trinh
David is an expert in all things plumbing, heating, cooling, and water treatment. He got his start in the plumbing business working on fixing all types of home improvement issues including water leaks, broken toilets, appliance installation, and more. Over time, he learned a ton about installing and choosing the correct water treatment products for homeowners.

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