Ecosmart ECO 18 Review

Read time: 5 minutes Last Updated: 10/10/2019

Ecosmart ECO 18

  • Built-in self-modulating technology
  • 2.5 GPM average, with a 4.4 GPM max
  • 99.8% energy efficiency for enhanced utility bill savings
  • Lifetime warranty
  • A little pricey, especially when factoring in shipping costs
Dimensions & Capacity:
3.6 x 14 x 17 inches
Fuel Type:
Flow Rate & Water Pressure:
2.5 GPM (average), 150 PSI (max)
Heating Capacity:
80° F - 140° F
Energy Efficiency Ratings & Certifications:
Lifetime warranty
Display Type:
Material Composition:
Copper, stainless steel
Our Review

The Ecosmart ECO 18 is geared towards performance, through and through, and is able to instantaneously keep up with the hot water demands of a growing family in a midsized home. Neither do the Ecosmart Eco 18’s features nor its core specifications leave much to be desired, especially when it comes to saving water and electricity. As a result, the Ecosmart ECO 18 is among the best options for homeowners looking to decrease their utility bills while also decentralizing their home’s hot water production system.

Unlike some tankless water heaters, which can only be used in certain parts of the country, the Ecosmart Eco 18 can be used efficiently wherever you live in the United States. At a minimum, this model is able to output 1.8 GPM of hot water in northern regions with frigid groundwater. At a maximum, this model can reach up to 4.4 GPM in the warmer American South. Regardless of your geographical location, the Ecosmart ECO 18 will be able to serve your home’s hot water needs without complaint.

All things considered, we gave the Ecosmart ECO 18 a final rating of 8.5/10. It certainly lives up to its title, “Best Mid-Sized Tankless Water Heater under $500.”

Read more about our how our ratings broke down for the ECO 18 below or checkout how it compares to other whole house tankless electric water heaters.

Why Might I Want this Specific Tankless Water Heater?

While comparing prospective tankless water heater options, you may opt for the Ecosmart Eco 18 if you want to cut back on how much electricity you spend on water heating in your home. This model only requires 75 amps of power to operate efficiently, with 99.8% of that electricity being converted into heat in this unit’s heating chambers. This model’s self-modulating technology makes this remarkably high energy efficiency rating possible, regardless of how much hot water you use daily.

Also, this model makes ample use of copper and stainless steel components throughout its internal and external construction. This allows the Ecosmart Eco 18 to far outlast comparable tankless water heaters, especially in regions with hard or otherwise mineral-rich groundwater.

Key Specifications and Features to Look for in a Tankless Water Heater


Size and shape can influence your specific tankless water heater model choice. Simply put, if a given model is too large, you’ll have a lot of trouble installing in a convenient location that is easy to access for regular maintenance and use. You won’t likely face any kind of spacing issues with the Ecosmart Eco 18, though, because it measures up at compact and versatile 3.6 x 14 x 17 inches. That’s enough to earn an 8.5/10 from us.

Fuel Type

All tankless water heaters use either electricity, natural gas, or propane as a fuel source. Each of these fuel sources provide their own situational benefits and can be more or less affordable based upon localized utility prices. The Ecosmart Eco 18 is an electric-powered unit, making it among the most affordable to install and upkeep based upon fuel source considerations. We rate it an 8/10 in this category.

Flow Rate & Water Pressure

In tankless water heater terminology, flow rate describes how much groundwater a given unit can take in, heat, and output in a minute’s time. Often measured in gallons per minute or GPM, flow rate can affect an outlet point’s water pressure if it dips too far or too sporadically. The Ecosmart Eco 18 carries a 2.5 GPM average, allowing it to meet the hot water demands of both a sink and a shower at once. Could be better, but still, it’s enough to power a midsized home’s water heating needs, so we’re giving it a score of 7.5/10.

Heating Capacity

A tankless unit’s heating capacity describes the range of temperatures that it is capable of heating ground water to during regular operation. Those looking to use their tankless unit to accomplish cooking and sanitary should take this metric into strong consideration. Many contemporary models feature an 80° F – 140° F range, as seen in the Ecosmart Eco 18. We gave it a score of 8.5/10 in this category.

Energy Efficiency Ratings & Certifications

Those looking to cut their utility bills should pay special attention to a tankless unit’s energy efficiency rating, which describes (using a percentage) how much of a given unit’s input electricity is converted into the core heating process. This rating is sometimes paired with regulatory certifications to back up their credibility. The Ecosmart Eco 18 features a 99.8% energy efficiency rating, but sadly lacks any certifications. Still, we’re giving it a 9/10 for its near-perfect efficiency rating.


The Ecosmart Eco 18 carries a lifetime warranty, so it is priced only slightly higher than average for its size. It’s a bit pricey, but a lifetime warranty isn’t something you get from most water heater manufacturers, so we’re giving it an 8.5/10 in this category.

Display Type

All tankless units use some type of display in order for facilitate productive interactions with their user. Many contemporary units, such as the Ecosmart Eco 18, use a digital display while older, less user-friendly models still rely on a primarily analog display. The ECO 18’s intuitive digital display type warrants a well-deserved 8/10.

Material Composition

As with all Ecosmart models, the ECO 18 uses corrosion-free copper and stainless steel components in its heat exchangers, ensuring a long service life. We give it an 8.5/10 in this department.

Different Uses for a Tankless Water Heater

Decentralized In-Home Water Heating

Decentralizing your in-home water heating system comes with numerous benefits. First and foremost, a decentralized system is far easier to maintain due to its modular nature. Second, a decentralized water heating system can be set up in proximity to your high-demand locations, thus cutting down response time when a hot water tap is pulled. Finally, a decentralized water heating system eliminates single-location reliance, thus eliminating the chance of running out of hot water during peak demand.

Cutting Water and Electric Bills

Homes that use tankless water heaters like the Ecosmart Eco 18 routinely cut their utility bills by a noticeable amount. This is because tankless units eliminate the single largest cause of wasted water and electricity in a tank unit, that is, the tank itself. Without a tank, a tankless unit doesn’t need to waste either water or electricity to keep a pool of hot water on standby.