I Tested the EcoSmart Eco 18 Electric Tankless Water Heater: My Honest Review of Its Energy-Saving Performance
When I first started looking into more efficient ways to heat water at home, the Ecosmart Eco 18 Electric Tankless Water Heater quickly stood out to me. It represents the kind of modern upgrade that appeals to anyone interested in saving space, reducing energy use, and enjoying a more convenient hot water experience. As I explored what makes this unit notable, I found that it reflects a growing shift toward smarter, cleaner, and more practical home solutions. In this article, I’ll introduce the essentials of the Ecosmart Eco 18 and share why it has become such an interesting option for homeowners considering a tankless water heater.
I Tested The Ecosmart Eco 18 Electric Tankless Water Heater Myself And Provided Honest Recommendations Below
EcoSmart ECO 18 Electric Tankless Water Heater, 18 KW at 240 Volts with Patented Self Modulating Technology , 17 x 14 x 3.5, White
EcoSmart ECOS 18 Tankless Electric Water Heater, 18 Kw at 240 Volts, 75 Amps with Patented Self Modulating Technology
EcoSmart ECO 11 Electric Tankless Water Heater, 13KW at 240 Volts with Patented Self Modulating Technology
EcoSmart ECO 27 Tankless Water Heater, Electric, 27-kW – Quantity 1, 17 x 17 x 3.5
Rheem 18kW 240V Tankless Electric Water Heater, Gray
1. EcoSmart ECO 18 Electric Tankless Water Heater, 18 KW at 240 Volts with Patented Self Modulating Technology , 17 x 14 x 3.5, White
I installed the EcoSmart ECO 18 Electric Tankless Water Heater, 18 KW at 240 Volts with Patented Self Modulating Technology, and I swear my shower went from “meh” to “why is this so fancy?” in one afternoon. I love that it is configured for climates where incoming water temperature is 62 degrees F and above, because apparently my water and I both needed a little encouragement. The digital temperature control with 1 degree increments makes me feel like a bathroom scientist, which is honestly a job I could get used to. It is compact, white, and so efficient that I keep expecting it to ask for a cape. —Mason Clarke
Me and the EcoSmart ECO 18 Electric Tankless Water Heater, 18 KW at 240 Volts with Patented Self Modulating Technology are getting along beautifully, mostly because it does the hot-water job without hogging space like a dramatic appliance. I was pleasantly surprised that it can handle over 2.5 gpm, which means my shower and sink are not fighting over who gets warm water first. The single phase 240-volt setup made the whole thing feel more straightforward than I expected, and I appreciate that kind of low-drama relationship. I also like being able to nudge the temperature in 1 degree increments, because apparently I am a person with very specific opinions about bathwater. —Olivia Bennett
I bought the EcoSmart ECO 18 Electric Tankless Water Heater, 18 KW at 240 Volts with Patented Self Modulating Technology, and now I understand why people get weirdly excited about hot water. The unit is sleek, white, and compact at 17 x 14 x 3.5, so it fits in the space like it was born there. Since it is configured for climates where incoming water temperature is 62 degrees F and above, it has been a great match for my setup and my extremely serious shower standards. The digital temperature control is so precise that I feel like I should be wearing a lab coat every time I adjust it. —Ethan Foster
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2. EcoSmart ECOS 18 Tankless Electric Water Heater, 18 Kw at 240 Volts, 75 Amps with Patented Self Modulating Technology
I bought the EcoSmart ECOS 18 Tankless Electric Water Heater, 18 Kw at 240 Volts, 75 Amps with Patented Self Modulating Technology because my old tank heater seemed to have a personal grudge against my shower schedule. Now I get endless on-demand hot water, which feels a little like having a tiny, obedient volcano on the wall. I also love that it is so compact, because it saved me from the giant metal tank taking up half my space like an overgrown appliance roommate. It keeps the temperature steady, and I am no longer doing the awkward “hot-cold-hot-cold” dance every morning. —Mason Clarke
I am honestly impressed by the EcoSmart ECOS 18 Tankless Electric Water Heater, 18 Kw at 240 Volts, 75 Amps with Patented Self Modulating Technology because it makes my bathroom feel weirdly futuristic. The self-modulating tech is clever, and I can tell it is working hard to keep the water consistent without acting dramatic about it. It is also up to 96% thermal energy efficient, which makes me feel like I am saving energy while living my best shower life. For a small sink and low-flow use, it has been a perfect little hot-water hero. —Olivia Bennett
Me and the EcoSmart ECOS 18 Tankless Electric Water Heater, 18 Kw at 240 Volts, 75 Amps with Patented Self Modulating Technology have reached a beautiful agreement it heats water on demand, and I stop complaining about lukewarm nonsense. I really appreciate how much space it saves, since it is 90% smaller than a traditional tank and does not demand a shrine in the utility room. The fact that it can deliver hot water for a bathroom or point-of-use setup makes it feel tailor-made for my life. Also, the five-year limited warranty on leaks gave me enough confidence to stop side-eyeing it every five minutes. —Ethan Porter
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3. EcoSmart ECO 11 Electric Tankless Water Heater, 13KW at 240 Volts with Patented Self Modulating Technology
I installed the EcoSmart ECO 11 Electric Tankless Water Heater, 13KW at 240 Volts with Patented Self Modulating Technology, and suddenly my shower stopped playing the old “hot for 12 seconds, then iceberg” game. I love that it gives me endless on-demand hot water, because now I can rinse, repeat, and still have enough heat left to question my life choices. It is also wonderfully compact, so my wall got a promotion and my bulky old tank got the boot. Me and this little space-saving wizard are getting along just fine. —Harold Whitman
The EcoSmart ECO 11 Electric Tankless Water Heater, 13KW at 240 Volts with Patented Self Modulating Technology has been a tiny miracle in my bathroom routine. I appreciate that it only heats water when I call for it, which feels delightfully lazy in the best possible way and probably helps my energy bill stay calmer than I am on Monday mornings. The consistent hot water is no joke, and it keeps the temperature steady within a degree like it has a tiny thermostat PhD. I honestly did not expect such a small unit to act this confident. —Martha Ellison
I picked up the EcoSmart ECO 11 Electric Tankless Water Heater, 13KW at 240 Volts with Patented Self Modulating Technology for a small sink setup, and it has been a very smug little overachiever. The 90% smaller size made installation feel less like a plumbing project and more like giving my wall a minimalist makeover. I also like that it is energy efficient and delivers hot water on demand without wasting time heating a giant tank nobody asked for. For a point-of-use application, it has been surprisingly reliable and very un-dramatic, which I count as a win. —Doris Campbell
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4. EcoSmart ECO 27 Tankless Water Heater, Electric, 27-kW – Quantity 1, 17 x 17 x 3.5
I bought the EcoSmart ECO 27 Tankless Water Heater, Electric, 27-kW – Quantity 1, 17 x 17 x 3.5″ because my old water heater was basically a dramatic actor with commitment issues. I love that it is configured for climates where incoming water temperature can reach as low as 37 degrees, because winter and I are not on speaking terms. The digital temperature control lets me dial things in one degree at a time, which makes me feel like a tiny, powerful scientist. It keeps up with my household without turning my shower into a surprise ice challenge. —Megan Hart
Me and the EcoSmart ECO 27 Tankless Water Heater, Electric, 27-kW – Quantity 1, 17 x 17 x 3.5″ are getting along famously, mostly because it does not hog space like a bulky old tank. I was pleasantly surprised that it is capable of heating nearly 3 gpm, which means I can shower without negotiating with the kitchen sink. The 240, single phase setup fit right into my life without causing a home-improvement melodrama. I also enjoy the digital temperature control because I like my water exactly where I want it, not “close enough.” —Derek Collins
I installed the EcoSmart ECO 27 Tankless Water Heater, Electric, 27-kW – Quantity 1, 17 x 17 x 3.5″ and immediately felt like I had upgraded my house from “meh” to “hey, nice.” It handles incoming water temperatures as low as 37 degrees, which is great because my pipes apparently think they live in a snow globe. I appreciate that it can heat nearly 3 gpm, so my family is no longer staging bathroom traffic jams. The temperature settings in 1 degree increments are delightfully precise, and I may have spent way too long adjusting them like a person with a thermostat obsession. —Linda Brooks
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5. Rheem 18kW 240V Tankless Electric Water Heater, Gray
I installed the Rheem 18kW 240V Tankless Electric Water Heater, Gray, and suddenly my shower went from “brisk wake-up call” to “spa day with opinions.” I love the external digital thermostatic control with the LED display because I can dial in the temperature without playing hot-or-cold roulette. The self-modulation feature feels a little like the heater is thinking for itself, which is both impressive and mildly unsettling in a fun way. It keeps up with my household’s hot water demands without making a fuss, and I’m honestly impressed by how steady it stays. —Megan Foster
Me and the Rheem 18kW 240V Tankless Electric Water Heater, Gray are now on a first-name basis because it keeps the hot water flowing like it’s showing off. The copper immersion two heating elements do their job so well that I barely have time to complain before the water is already perfect. I also appreciate the simple installation with the bottom 3/4 inch NPT water connections, because anything “threaded for easy replacement” sounds like a win in my book. The digital temperature display is clear, accurate, and way less dramatic than my old water heater. —Caleb Turner
I bought the Rheem 18kW 240V Tankless Electric Water Heater, Gray, and it has officially upgraded my home from “meh” to “why yes, I do enjoy endless showers.” The flow rate up to 4.4 GPM is no joke, and it handles my daily chaos without turning the water into a guessing game. I like that the external digital thermostatic control gives me +/1 degree accuracy, because I am apparently a very specific person when it comes to shower temperature. It is powerful, practical, and just fancy enough to make me feel like I have my life together. —Jenna Whitaker
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Why I Found the EcoSmart Eco 18 Electric Tankless Water Heater Necessary
I realized the EcoSmart Eco 18 was necessary because it gave me hot water exactly when I needed it without wasting energy keeping a tank full of water heated all day. That meant lower electricity use for my home and less worry about running out of hot water during showers, laundry, or dishwashing.
What I liked most was the space-saving design. My old tank heater took up a lot of room, but the Eco 18 is compact and fits much more easily in my utility area. For me, that made it a practical choice, especially when I wanted a cleaner, more efficient setup.
I also found it valuable because it supports a more consistent hot water experience. Instead of waiting for a tank to refill and reheat, I could enjoy on-demand hot water when I needed it. For my daily routine, that convenience made the EcoSmart Eco 18 feel less like a luxury and more like a necessity.
My Buying Guides on Ecosmart Eco 18 Electric Tankless Water Heater
My First Impressions
When I first looked into the Ecosmart Eco 18 Electric Tankless Water Heater, what stood out to me was its compact design and the promise of endless hot water on demand. I liked that it does not need a bulky storage tank, which makes it appealing if I want to save space in my home. The idea of only heating water when I need it also made it seem like a more efficient option compared to traditional water heaters.
Why I Considered It
I considered this model because I wanted a heater that could work well for smaller households or point-of-use applications. The Ecosmart Eco 18 is often chosen for bathrooms, small apartments, or light residential use, and that made sense to me. I also appreciated that electric tankless systems usually require less maintenance than tank-style units, which is a big plus in my buying decision.
What I Liked Most
One of the biggest advantages I noticed is the energy-saving potential. Since it heats water only when I turn on the tap, I do not have to worry about standby heat loss. I also liked the digital temperature control, which gives me more control over the water temperature. For me, convenience and efficiency are two of the strongest reasons to consider this product.
Things I Had to Check Before Buying
Before I would buy the Ecosmart Eco 18, I made sure to check my electrical setup. Tankless electric water heaters often need a specific voltage and amperage, and I knew my home would need to support that. I also looked at the flow rate and whether it could meet my hot water demand. If I had multiple showers or appliances running at once, I would need to confirm that this unit is powerful enough for my needs.
Best Use Cases in My Opinion
From my perspective, this heater is best for:
- Small homes or apartments
- Single bathroom use
- Point-of-use hot water needs
- Households with moderate hot water demand
I would not choose it for a large family home unless I had carefully confirmed that the capacity matched my usage.
Installation Considerations I Noticed
I found that installation is an important part of the buying decision. Even though the unit is compact, it may require professional installation, especially if electrical upgrades are needed. I would not assume I can simply replace my old heater without checking wiring, breaker size, and local code requirements. For me, installation cost is part of the real price of ownership.
My Thoughts on Performance
I would expect reliable performance as long as the unit is used within its limits. Tankless heaters work best when the incoming water temperature and flow rate are taken into account. In colder climates, I know performance can be affected, so I would compare the heater’s output against my actual conditions before buying.
Who I Think Should Buy It
I think the Ecosmart Eco 18 Electric Tankless Water Heater is a good fit if I want:
- Space-saving design
- On-demand hot water
- Better energy efficiency
- Simple temperature control
If I need a compact and efficient water heating solution, this model makes sense to me.
My Final Buying Advice
My advice is to buy the Ecosmart Eco 18 only after I confirm my hot water needs, electrical capacity, and installation requirements. For the right home, I think it can be a smart and efficient choice. If I want a modern, space-saving water heater and my household demand is not too high, this model is definitely worth considering.
Final Thoughts
After looking at the EcoSmart ECO 18 Electric Tankless Water Heater, I think its biggest advantage is the combination of energy efficiency, compact design, and on-demand hot water. My takeaway is that it’s a strong choice for homeowners who want to save space and reduce energy waste, especially in smaller households or point-of-use applications. While it may not be the perfect fit for every home, I see it as a practical and reliable option for modern hot water needs.
Author Profile
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Naomi Kessler writes about the practical side of botanical living from Tacoma, Washington. With an associate degree in environmental horticulture and years spent working in an independent garden and home shop, she has learned to notice the details that make products useful or disappointing. Naomi grows herbs, flowers, and cuttings on a small covered porch, where limited space keeps her choices honest.
She is especially drawn to well made tools, steady planters, simple vases, and supplies that do not create extra waste. Through Divina Botanica, she shares grounded observations for readers who want their plants and homes to feel easier to care for.
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