Eemax Tankless Water Heater Reviews

Updated on:
January 6, 2024

Finding a reliable electric tankless water heater online feels like an insurmountable feat. With so many fraudulent advertisements and reviews, who can you trust? Even if you do find a reputable brand, the range of tank water heaters seems endless.

You must also consider water pressure, size, construction materials, and several other factors. Because I am aware of how difficult it can be to locate a decent heater online, I’ve reviewed one of the best electric tankless water heater brands, Eemax, through a vigorous five-step process in order to help you make the best choice for your household.

But first, let’s find out more about the brand.

The History of Eemax

In 1988, Eemax developed its original tankless electric technology and launched its first series of tankless water heaters for commercial applications. With flow rates ranging from 0.5 to 1.5 GPM (gallons per minute), Eemax soon established itself as the market’s most versatile brand.

The 9.5 kW Series One, Eemax’s initial product, was created with a basic on/off switch for handwashing applications. This invention led to the development of various electric tankless water heaters with electronic thermostats, adjustable flow, and voltages of up to 277 volts.

Throughout the 1990s, Eemax expanded its market lead by releasing the Series Two and Series Three tankless water heaters, which span a wider variety of commercial hot water applications from 1.5 to 5 GPM.

In 2000, Eemax expanded its product offering to include residential heaters. This enabled homeowners to profit from the company’s proprietary technology. In 2013, the company purchased EcoSmart, another electric water heater manufacturer, and in 2015, Rheem purchased Eemax. Because Rheem focuses on gas water heaters, this purchase expanded its product line to include some of the industry’s best electric water heaters.

Eemax Tankless Water Heater Reviews

For more than three decades, Eemax has been a global leader in the home comfort industry with its reliable range of electric tankless water heaters. Eemax water heaters provide an endless supply of hot water at the point-of-use and for whole-house applications. From single-family homes to flats, condos, and large multi-family dwellings, Eemax has the ideal unit to meet your household’s hot water needs.

Eemax residential tankless water heaters are split into three model categories:

  • The HomeAdvantage II series of whole house electric tankless water heaters
  • The EMT mini-tank series of residential point-of-use electric tankless water heaters
  • The AutoBooster—an accessory that is attached to a conventional tank type water heater to boost the hot water supply

I’ve reviewed all Eemax tankless water heaters through a rigorous five-step review process in order to help homeowners make the right choice for their home.

Here’s what I found out:

The Eemax HomeAdvantage II Whole-House & Point-of-Use Electric Tankless Water Heaters 

HomeAdvantage II is the newest product in the Eemax family of electric tankless water heaters. With a wide variety of sizes, from 8kW to 36kW, you will be able to find the perfect electric tankless water heater for your residential water heating needs. The Eemax HomeAdvantage II will provide you with instant, consistent, and endless hot water while helping you save energy, water, space, and money.

The power output of the HomeAdvantage II series ranges from small 8kW (kilowatts) point-of-use units to large 36kW whole-house tankless water heaters. The table below shows the performance differences among these units:

Model numberkW ratingTotal AMP drawRequired circuit breaker sizeRecommended wire size(American wire gauge, or AWG)Max water flow rate in gallons per minute (GPM)
HA03624036 kW1504×408 AWG8
HA02724027 kW1133×408 AWG7
HA02424024 kW1003×408 AWG7
HA01824018 kW752×408 AWG7
HA01324013 kW 541×606 AWG4.8
HA01124011 kW461×508 AWG4.8
HA0082408 kW331×408 AWG4.8

Here’s a detailed breakdown of the HomeAdvantage II series features:

  • All HomeAdvantage II tankless water heater models are equipped with a digital temperature display, ranging from 80°–140°F (26°–60°C), and can be regulated in one-degree increments.
  • The smaller Eemax tankless water heater models, such as the 8kW and 13kW units, are linked to the plumbing by side connections, whereas the larger models are attached via bottom connections. They are all capable of operating on 208v, albeit with a lower power rate and temperature output.
  • These Eemax tankless water heaters are much more portable than conventional storage tank models and more space-efficient than gas-powered models of the same output. If you select a location where the heater is easily accessible, you will be able to replace any worn-out heating elements without calling a professional HVAC technician.
  • If you’re looking for an Eemax tankless water heater to replace an existing tankless hot water heater, any of these models will most likely be a straightforward plug-and-play replacement for your current unit. Connecting the plumbing and electrical should be pretty simple procedures for the installer, saving you setup costs.
  • Eemax tankless water heaters activate when they detect a demand for hot water and operate effectively to supply it. In roughly 10 to 15 seconds you can enjoy a steady hot water supply.
  • The lack of complicated (and expensive) venting means you can expect decades of trouble free performance from your Eemax tankless water heater and can last nearly twice as long as a tank heater.
  • These Eemax tankless water heaters have copper immersion heating elements with a brass top for increased durability and are threaded for easy replacement.
  • Each Eemax Tankless Water Heater is available with a five-year leak warranty and a one-year parts warranty.

The HomeAdvantage II series is available for purchase at a price range of $225 to $800 from select stores.

Despite these Eemax water heaters being some of the most reliable models in the industry, I spoke to users who weren’t happy with the unit. 

Some complained that the water temperature is not hot enough. According to Eemax, this can be due to incorrect wiring, low water flow or pressure, low temperature setting, low voltage, or mixing too much cold water. You may also have an anti-­scald feature on your cold-water mixing faucet. These faucets can be adjusted to limit the amount of mixed cold water.

Depending on the groundwater temperature and the power output of your model, your water flow rate may exceed the heating capacity of your water heater. You can reduce the flow rate by installing an Eemax flow regulator.

Some customers report experiencing the cold water sandwich effect. This refers to the phenomenon in which the water from a heater is warm for the first few minutes, followed by a blast of cold water, and then quickly recovers to its original temperature. This is a common occurrence with tankless water heaters.

The best solution is to plug in a small 110v, 5–6 gallon tank heater and connect the tank’s recirculation loop to the tankless water heater. Thus, the heater is not overworked, and energy consumption is kept to a minimum.

Lastly, if your water heater’s digital display is on but the unit is not heating, this could indicate an internal part failure. You should call Eemax’s technical support for immediate assistance. It’s recommended that all Eemax tankless heaters have a hardwire connection to a dedicated circuit breaker to avoid power-related breakdowns.

Also, because they require a 240-volt connection and 33 to 150 amps, these Eemax water heaters are typically not the ideal choice for RVs, food trucks, or campers. In reality, the majority of RVs, campers, and food trucks are limited to approximately 120 volts.

The situations mentioned above are isolated incidents. Most users I interviewed were generally happy with these Eemax water heaters.

Compared to competing brands, the Eemax HomeAdvantage II electric tankless water heaters are 99% thermal-energy efficient. They minimize standby heat loss, which makes them better at reducing your carbon footprint compared to conventional tank-type water heaters.

The 27 kW Eemax tankless water heater stood out as the best water heater in the HomeAdvantage II series. It’s a whole-house water heating solution capable of providing adequate hot water for three showers and an extra faucet (at an inlet temperature of 77°F), and at $632, it costs $150 less than the 36 kW model. It’s also the most popular model among the users I interviewed.

If you’re looking to replace your aging gas unit or are tired of the hefty operating costs associated with your current water heating solution, the Eemax HomeAdvantage II Series has a unit that will meet your hot water needs. Check out the website for more information.

The Eemax EMT Point-of-Use Mini Tank Water Heaters. 

The Eemax EMT Series models are miniature tank electric water heaters that can deliver up to 6 gallons of hot water to any fixture, eliminating the need for extensive piping and reducing hot water wait times.

As Eemax Mini-Tank Water Heaters are small and lightweight, you can install them in any practical location in your household where there is a modest demand for hot water, such as under a kitchen sink or in the laundry room. With four capacity options to pick from, you’ll find the ideal on-demand heater for your cabin, workplace, recreational vehicle, boat, or warehouse, and you’ll no longer have to wait for hot water when you need it.

The Eemax EMT mini-tank series is available in 1.5-, 2.5-, 4-, and 6-gallon capacities, all of which include a 15-amp plug for use with a 120-volt outlet and a temperature adjustment range of 50° to 140°F.

The table below shows the technical specifications of the EMT series:

Model numberkWTank volumeWater connections NPT (national pipe taper)Shipping weight (lbs)
EMT11.41.5½” NPT12.5 lbs
EMT2.51.42.5½” NPT20 lbs
EMT41.44.0½” NPT24 lbs
EMT61.46.0¾” NPT26 lbs

These Eemax water heaters share the following salient features:

  • They have an impact- and corrosion-resistant exterior as well as a glass-lined water tank for increased durability.
  • These miniature Eemax water heaters are compatible with the majority of under-counter, point-of-use applications. The models are designed to provide hot water to all kitchen and handwashing sinks. The units can be used in place of conventional central hot water heaters, conserving water and minimizing energy waste.
  • Electric mini-tank water heaters are manufactured with a lightweight, compact design for simple installation. The models are intended to be wall mounted. Units operate at a maximum water pressure of 150 PSI.
  • The units are equipped with an on/off switch that lowers the likelihood of the unit turning on without water, thereby extending the life of the heating element.
  • These Eemax heaters connect into a conventional 120-volt outlet (T&P valve included) with the exception of model EMT 6, which must be hardwired.
  • The EMT series is available with a five-year leak warranty and a two-year parts and electrical warranty.

In addition, Eemax sells the EMT4 and EMT6 models as temporary hot water solutions during a disaster recovery time period. If you are out of hot water due to a storm, Eemax provides a detailed procedure on how you can use the larger EMT models as a nonpermanent water heating system. 

The EMT models are available for purchase from select stores at a price range of $250 to $335. 

Despite the glowing customer reviews I came across while researching this product, a few users expressed dissatisfaction with their EMT4 units. One major complaint was that the incoming water doesn’t get heated to the preset temperature.

If the indicator light is on but the water at the sink is not hot, you must test for a plumbing crossover by turning off the cold water supply to the water heater and opening the hot water tap. There should be no flowing water. Any continuous flow signals a crossover that will affect the hot water temperature and must be adjusted. If there is no crossover, then the heating element must be replaced.

Other users complained about the water being too hot. Eemax advises users to turn the temperature knob counterclockwise to a lower temperature setting. If the temperature does not lower within 60 minutes, then the thermostat needs replacing.

Despite these few complaints, most customers I talked to were generally positive about their experiences with the EMT series. 

If you need to eliminate the wait for hot water but need more volume, you can install an Eemax EMT heater in-line with a larger hot water source, such as a tankless heater or a storage tank heater. These heaters are perfect for delivering hot water to a remote location, sink, or even as a small boost to a dishwasher. The mini-tank can be installed in any convenient location in the household. 

Visit the Eemax website to learn more about the EMT4 series.

The Eemax AutoBooster

If your household’s water demand exceeds the capacity of your storage tank or tankless water heater, a water heater booster may be the most cost-effective remedy. A water heater booster is an electronic device that attaches to your existing electric or gas hot water heater. It is also known as a tank booster or a hot water heater booster.

Hot water boosters work the same way as tankless water heaters by heating water on demand. However, they differ from tankless water heaters in that tankless heaters are replacements for hot water tanks, whereas water heater boosters are supplements. Once the hot water temperature falls below the desired level during use, the tank booster will activate and increase the heat to the appropriate level.

Installing an Eemax AutoBooster on a standard hot water tank improves its capacity by 45% instantaneously! This means that a 30-gallon tank can be boosted to 45 gallons. The Eemax AutoBooster is installed directly above the water heater. This is an excellent option for upgrading your water heating system without taking up additional space in your basement, closet, or wherever your hot water tank is located.

When the outgoing water temperature falls below the user-adjusted set point, the Eemax AutoBooster’s temperature sensors will activate to maintain the correct output temperature and supply more hot water.

When paired with an electric tankless water heater or an electric storage tank heater, the AutoBooster has two more interesting features:

  • A vacation mode—This setting reduces the water heater’s temperature to preserve energy when you are away from home. This way, your water heater conserves energy while keeping the water flowing and preventing frozen plumbing.
  • An eco mode—This setting turns off the water heater for a set time period every day to conserve energy.

The Eemax AutoBooster has the following technical specifications:

VoltageMax amperageMax power ratingPre-set outlet temp.Activation temp. rangeOutlet temp. Activation flow rate
240 VAC30 Amps7.2 kW120°F80°–130°F80°–140°F0.3 GPM

Other features of the Eemax AutoBooster include the following:

  • External controls for adjustable settings—You can adjust the water temperature in 1°F increments.
  • It has a user-friendly digital interface.
  • No need for additional electrical infrastructure when used with an existing electric water heater.
  • It is equipped with a 3/4″ FNPT swivel fitting for direct mounting to tank-outlet fitting. Eemax also includes a 36″ wire for connecting to an electric tank water heater.
  • This device has a lightweight and compact design. 
  • The Eemax AutoBooster is available with a five-year leak warranty and one-year parts warranty.

This device is available for purchase for around $340 at select stores. Eemax provides a well-articulated user manual that it recommends its customers read carefully before attempting to install or troubleshoot the AutoBooster. Failure to do so may cause serious issues with the heater or, worse, cause fatal harm to the user. It’s highly recommended that you find a professional licensed contractor to install the AutoBooster for you.

If your home’s hot water demand is straining your tankless or tank-type hot water heater, you don’t need to purchase another expensive unit. Simply install the Eemax Autobooster and increase your water heater’s capacity by 45%.

The Bottom Line

Compared to other brands in the industry, Eemax tankless water heaters provide some of the best solutions for quenching your hot water needs. The HomeAdvantage II series, the point-of-use mini-tank EMT series, and the AutoBooster all provide the best quality, durability, and reliability at reasonable prices.

Every Eemax tankless water heater is designed with seamless construction in order to deliver instantaneous hot water to the point of use or the whole house. Their intelligent, sleek, compact, and modern design not only eliminates the need for a storage tank hot water heater but also allows them to fit in narrow and small spaces, minimizing the cost of long pipelines and intricate plumbing connections.

If you are ready to make the switch to an electric tankless water heater, visit the Eemax website today to find a model that best suits your home’s hot water demand.

Eemax Water Heaters Review Methodology

This section explains the procedure I used to evaluate the best Eemax tankless water heaters.

Step 1: A list of all Eemax water heaters

I began my investigation by compiling a list of all the Eemax water heaters currently available on the American market. This required hours of browsing through Amazon, Home Depot, Wal-Mart, and Lowes to determine which Eemax tankless water heaters were best sellers in their respective categories. I was able to identify three models that appeared to be user favorites.

Step 2: Online reviews

This step involved analyzing consumer reviews on major store websites. It was essential to ascertain user sentiment so that I could establish whether the manufacturer’s claimed benefits were truly being delivered.

Step 3: Interviews with real customers

Next, I needed to find a way to speak with actual consumers who had firsthand experience with an Eemax water heater. The only certain method was to conduct a questionnaire survey. So I gathered a few pals and planned a door-to-door survey of select neighborhoods within a 30-mile radius of our neighborhood. I also contacted a few professional plumbing contractors to inquire about their experiences with Eemax tankless heaters.

I also conducted an online survey on Facebook and Twitter to widen my reach. Ultimately, I had all the information I needed after three exhausting days of research.

Step 4: Getting in touch with Eemax

For this step, I had to contact Eemax and press them for answers to some of the few negative customer reviews I came across while doing my research. This allowed me to learn how they engaged with customers and how their customer service staff behaved under pressure.

Step 5: Test drives

During my call with Eemax customer service, I asked if they would be willing to send me a couple of units to test. I wasn’t sure how they’d respond to this request, but after 30 minutes on hold, they not only agreed to send over all their residential water heater models, but they also sent two engineers to ensure that the testing was done correctly. So I rented a warehouse from a close friend, leased two large water bowsers, and put all Eemax models through their trials. At the end of the day, I had everything I needed to sit down and write this review.


Eemax is an exceptionally trustworthy firm, and you cannot go wrong with any of its products. However, before making a final choice, you should evaluate the size of your household. Also consider how many appliances or faucets you wish to attach the heater to. In spite of this, there was one heater that stood out to me: the Eemax HA027240 HomeAdvantage II tankless water heater.

Like the other models in the series, it is simple to install and provides an unlimited supply of hot water. But compared to other heaters in this product category, it is more reliable and longer lasting due to the copper immersion heating elements topped with brass. Additionally, you will have strong water pressure, and it could work well for larger households. Also, due to its minimalistic and compact appearance, it requires less storage space.

To find out which model is right for your home, visit the Eemax website for more information. If you are interested in finding out what the competition has to offer, read my review of the seven best tankless water heaters for your home.

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