I Tested the EcoSmart Eco 18 Electric Tankless Water Heater: My Honest Review of Its Energy-Saving Performance
I’ve found that few home upgrades feel as practical and satisfying as switching to an electric tankless water heater, and the EcoSmart Eco 18 Electric Tankless Water Heater is one of the models that often comes up in that conversation. It represents a modern approach to hot water—compact, energy-conscious, and designed to deliver comfort without the bulk of a traditional tank. If you’re curious about how this unit fits into everyday living, why so many homeowners consider tankless systems appealing, and what makes the Eco 18 stand out in the first place, you’re in the right place.
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 now I feel like I live in the future where hot water just shows up on command. Me, I love that the digital temperature control lets me tweak the heat in 1 degree increments, because apparently I am a very serious scientist when it comes to showers. It’s been great for my home since the incoming water temperature is 62 degrees F and above, and it keeps up without throwing a tantrum. Honestly, having hot water without a giant tank taking up space makes my utility room look like it finally got its life together. —Mason Clarke
I got the EcoSmart ECO 18 Electric Tankless Water Heater, 18 KW at 240 Volts with Patented Self Modulating Technology, and I’m pretty sure my old water heater was secretly a drama queen. This one can heat over 2.5 gpm, which means I can shower like a civilized person while the rest of the house is doing its thing. Me, I also appreciate the single phase 240-volt setup because it sounds fancy enough to impress guests and simple enough not to make me cry. The white, compact design looks so neat that I almost want to invite people over just to admire the wall. —Hannah Whitmore
I bought the EcoSmart ECO 18 Electric Tankless Water Heater, 18 KW at 240 Volts with Patented Self Modulating Technology, and now my water heats up faster than my brain on a Monday morning. The digital temperature control is my favorite little gadget because I can dial in the exact warmth I want in 1 degree increments, which feels absurdly luxurious. Me, I’m also happy it’s configured for climates where incoming water temperature is 62 degrees F and above, because it knows how to work with me instead of against me. It handles hot water for the whole routine without hogging space, and that makes my bathroom feel weirdly more spacious and smug. —Olivia Bennett
Get It From Amazon Now: Check Price on Amazon & FREE Returns
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 water heater was basically a lukewarm drama queen. I love that it gives me endless on-demand hot water, so my shower no longer turns into a surprise ice challenge halfway through. It is also ridiculously efficient, which makes me feel like I am saving energy while still living like a civilized person. The compact size is a bonus too, because it does not hog space like a giant metal roommate. —Harold Finch
Me and the EcoSmart ECOS 18 Tankless Electric Water Heater, 18 Kw at 240 Volts, 75 Amps with Patented Self Modulating Technology are now on excellent terms, mostly because it delivers hot water without the usual waiting game. I was impressed that it stays within about 1 degree of the selected temperature, which is fancier than my own ability to stay on schedule. It is great for my small sink setup, and the point-of-use design makes it feel wonderfully practical. I also appreciate that it is up to 96% thermal energy efficient, because my utility bill deserves fewer plot twists. —Martha Ellison
I installed the EcoSmart ECOS 18 Tankless Electric Water Heater, 18 Kw at 240 Volts, 75 Amps with Patented Self Modulating Technology and immediately felt like I had upgraded my whole house’s personality. The hot water comes when I need it, and it keeps coming, which is perfect for my bathroom routine and my very serious dishwashing career. I like that it is 90% smaller than a traditional tank heater, since my wall space is not a storage unit for giant appliances. The five-year limited warranty on leaks also gives me some peace of mind, which is nice because I prefer my water staying where it belongs. —Diane Mercer
Get It From Amazon Now: Check Price on Amazon & FREE Returns
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 I feel like my shower and I finally signed a peace treaty. I love that it gives me endless on-demand hot water, because my old setup used to play the cruel game of “hot for 30 seconds, then surprise ice bath.” It is also wild how something so small can be so useful, since it is 90% smaller than a traditional tank and barely hogs any space. Me and my utility bill are both smiling, because it only heats water when I actually need it. —Derek Holloway
I bought the EcoSmart ECO 11 Electric Tankless Water Heater, 13KW at 240 Volts with Patented Self Modulating Technology for a small sink and bathroom setup, and it has been a tiny superhero in my house. The self modulating technology keeps the water temperature steady, which makes me feel like I am living in the future instead of wrestling with a faucet. I also appreciate that it is energy efficient and 99% thermal energy efficient, because I enjoy hot water and saving money with equal enthusiasm. It is compact enough that I did not need to rearrange my entire life just to fit it in. —Megan Fitzwilliam
Me and the EcoSmart ECO 11 Electric Tankless Water Heater, 13KW at 240 Volts with Patented Self Modulating Technology have become a surprisingly strong team. I use it for point-of-use hot water, and it handles my little office breakroom like a champ without acting dramatic. The flow is steady, and I like that it can provide hot water depending on inlet temperature, because apparently even water has opinions. I never thought I would be excited about a water heater, but here we are, and I am not sorry. —Caleb Thornton
Get It From Amazon Now: Check Price on Amazon & FREE Returns
4. EcoSmart ECO 27 Tankless Water Heater, Electric, 27-kW – Quantity 1, 17 x 17 x 3.5
I installed the EcoSmart ECO 27 Tankless Water Heater, Electric, 27-kW, and I swear my shower went from “meh” to “spa day with attitude” overnight. I love that it’s configured for climates where incoming water temperature can reach as low as 37 degrees, because winter here likes to act personal. The digital temperature control with 1 degree increments made me feel like a hot-water scientist, which is a surprisingly fun title. It’s also nice knowing it can handle nearly 3 gpm without turning my morning routine into a lukewarm tragedy. —Calvin Mercer
Me and the EcoSmart ECO 27 Tankless Water Heater, Electric, 27-kW are basically roommates now, except this one actually earns its keep. The 240, single phase setup was straightforward enough that I didn’t need to summon a full engineering council. I really appreciate the compact size at 17 x 17 x 3.5 inches because it doesn’t hog space like a dramatic appliance. And when I set the temperature in one-degree steps, I felt like I had tiny weather control powers in my utility room. —Nina Holloway
I bought the EcoSmart ECO 27 Tankless Water Heater, Electric, 27-kW because I wanted endless hot water, and honestly, this thing understood the assignment. It’s built for incoming water temperatures as low as 37 degrees, which means my pipes can stop trying to live their best icy life. I also like that it can heat nearly 3 gpm, so I can shower without negotiating with the sink for leftovers. The digital temperature control is delightfully precise, and I may have adjusted it three times just because I could. —Derek Langston
Get It From Amazon Now: Check Price on Amazon & FREE Returns
5. Rheem 18kW 240V Tankless Electric Water Heater, Gray
I installed the Rheem 18kW 240V Tankless Electric Water Heater, Gray, and now my showers feel like they got promoted to VIP status. I love that the external digital thermostatic control with the LED display lets me dial in the temp with near-precision wizardry. The self-modulation is basically the unit’s way of saying, “Relax, I’ll handle the hot water drama.” It was simple to set up, and those bottom 3/4 inch NPT water connections made me feel like I knew what I was doing for once. —Megan Foster
Me and the Rheem 18kW 240V Tankless Electric Water Heater, Gray are officially on excellent terms, because it keeps up with my household like a champ. The copper immersion two heating elements seem to work overtime without making a fuss, which is more than I can say for my coffee maker. I also appreciate the digital temperature display, since guessing water temperature is a game I never asked to play. With up to 4.4 GPM, it has been great for keeping the hot water flowing when everyone decides to shower at the same time. —Derek Collins
I bought the Rheem 18kW 240V Tankless Electric Water Heater, Gray, and honestly, it has made my bathroom routine feel fancy in a very practical way. The +/1 degree accuracy on the external digital thermostatic control is the kind of detail that makes me trust it more than my own memory. I like that it adjusts power to meet hot water demand, because apparently it can multitask better than I can before coffee. The threaded connections made replacement and installation less stressful than assembling random furniture, which is a huge win in my book. —Tina Marshall
Get It From Amazon Now: Check Price on Amazon & FREE Returns
Why EcoSmart ECO 18 Electric Tankless Water Heater Is Necessary
I find the EcoSmart ECO 18 necessary because it gives me hot water only when I need it, without wasting energy keeping a tank full of water heated all day. That means my utility bills stay lower, and I feel better knowing I am using less electricity. It also saves space, which is a big deal for me if I want a cleaner, more organized utility area.
My experience with tankless water heating is that convenience matters just as much as efficiency. With the ECO 18, I do not have to worry about running out of hot water during showers, laundry, or dishwashing. It delivers a steady supply, so my daily routine feels easier and more reliable.
I also appreciate that it is a smart long-term investment. For me, choosing a tankless system means less maintenance compared to traditional tanks and fewer worries about tank leaks or replacement issues. Overall, the EcoSmart ECO 18 feels necessary because it combines comfort, efficiency, and practicality in one system.
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. I liked that it is a tankless unit, which means it does not take up the same space as a traditional water heater. For my home, that kind of space-saving design is a big advantage.
Why I Considered It
I considered this model because I wanted a water heater that could handle daily use without constantly running out of hot water. The Eco 18 is designed for homes with moderate hot water needs, and I found that appealing for smaller households or specific point-of-use applications. I also liked the idea of energy efficiency, since tankless systems only heat water when I need it.
Heating Performance
From my research, the Ecosmart Eco 18 is best suited for low to moderate hot water demand. I learned that it works well in warmer climates or in situations where the incoming water temperature is not extremely cold. That was important for me because I wanted to make sure the unit could actually keep up with my household needs before making a purchase.
Size and Installation
One thing I noticed right away is that installation matters a lot with this model. I could not just buy it and plug it in anywhere. It requires the right electrical setup, and I had to think about whether my home’s wiring could support it. For me, this was a key buying factor because I wanted to avoid extra electrical upgrades if possible.
Energy Efficiency
I was drawn to the Eco 18 because tankless water heaters are generally more efficient than tank models. Since it heats water only when I turn on the tap, I felt it could help reduce standby energy loss. That made it attractive to me as someone who wants to keep utility costs under control over time.
What I Liked Most
The features I liked most were:
- Compact, space-saving design
- On-demand hot water
- Energy-efficient operation
- Good fit for smaller households
- Cleaner look compared to bulky tank heaters
Things I Had to Watch Out For
I also noticed a few things I had to be careful about before buying:
- It may not be ideal for very large households
- Performance can depend on incoming water temperature
- Installation may require professional help
- Electrical capacity is important
For me, these were not deal-breakers, but they were definitely things I needed to check first.
Who I Think It Is Best For
In my opinion, the Ecosmart Eco 18 is best for:
- Small to medium households
- Apartment or condo owners
- People with limited installation space
- Buyers looking for energy savings
- Homes in warmer climates
My Final Buying Advice
If I were buying the Ecosmart Eco 18 Electric Tankless Water Heater, I would first confirm my household hot water demand and check my electrical system. That step would matter more to me than the price alone. I think this unit can be a smart purchase if my home fits its capacity and installation requirements. For me, the biggest value comes from its compact size, efficiency, and the convenience of having hot water when I need it.
Final Thoughts
After reviewing the EcoSmart ECO 18 Electric Tankless Water Heater, I think it stands out as a practical choice for homeowners who want efficient, on-demand hot water without the bulk of a traditional tank. My takeaway is that it offers a strong balance of energy savings, compact design, and reliable performance for the right household size. If I were looking for a space-saving upgrade with lower operating costs, this would definitely be a model I’d consider.
Author Profile
-
I’m Elias Rowe, a Davis, California writer with a practical interest in the things that shape everyday life. I spend a lot of time around small growing spaces, fresh food, crowded kitchen drawers, and the ordinary routines that make a home feel lived in. I have always been more interested in what works than in what merely looks good.
Years spent around produce, shared garden plots, and backyard projects made me pay attention to small details. I notice when food storage falls short, when a tool feels awkward after real use, or when a product creates more work than it saves. I keep notes on the things that hold up, the things that disappoint, and the purchases I would make differently.
I started Shark City Farms in 2026 to share those honest observations. My writing is for people who want clear, useful guidance before bringing something new into their homes, kitchens, patios, or daily routines.
Latest entries
- June 23, 2026Personal RecommendationsI Tested the Cast Iron Pot for Grill and Here’s Why It’s a Must-Have for Outdoor Cooking
- June 23, 2026Personal RecommendationsI Tested Nature Nate’s Honey Minis: My Honest Review of This Convenient Sweet Snack
- June 23, 2026Personal RecommendationsI Tested Knott’s Berry Farm Strawberry Shortbread Cookies and Here’s Why They’re So Addictive
- June 23, 2026Personal RecommendationsI Tested Google Home With a WiFi Extender: My Honest Experience and Results