EcoSmart 18 kW Self-Modulating 3.5 GPM Electric Tankless Water Heater-ECO 18 - The Home Depot


Model # ECO 18

Internet # 203316216

Store SKU # 1000047991

18 kW Self-Modulating 3.5 GPM Electric Tankless Water Heater

EcoSmart 18 kW Self-Modulating 3.5 GPM Electric Tankless Water Heater

This item has been discontinued.
The Home Depot no longer carries this specific product.

$362.06 / each
  • Perfect for apartments with up to 3 people
  • Requires 2 x 40 Amp Double Pole Breakers
  • Heats 2 showers and 2 sinks simultaneously in warm climates


Model # ECO 18

Internet # 203316216

Store SKU # 1000047991

Store SO SKU # 1000094374

EcoSmart Electric Tankless Water Heaters, also called Instantaneous On Demand Water Heaters, provide endless hot water on demand and only as needed. Self-modulating flow sensor technology regulates the amount of energy required to heat the water needed. This Smart Technology electric tankless water heater is configured for climates where incoming water temperature is 62°F and above. The ECO 18 is capable of heating over 2.5 GPM, which is the equivalent of one shower head (with a 1.5 GPM flow) and one sink with a low inlet water temperature of 62°F. Two showers can be run simultaneously when incoming water temperature is above 70°F in warmer climates such as South Texas, South Florida, New Mexico, Arizona and South California.

  • Lifetime warranty
  • Patented self-modulating technology and design
  • Never run out of hot water with an EcoSmart tankless water heater
  • Digital temperature control allows you to set your temperature in increments of 1°
  • All EcoSmart electric tankless water heaters come with an automatically resettable thermostat as opposed to a manually resettable thermostat; the integration of all components and quick connections are designed to promote simplicity for the installer and the user
  • Prior to purchase and installation please verify this model is the rights size for your hot water needs and electrical requirements
  • Refer to the info and guides for help with: location specifications map, installation, and troubleshooting
  • Tankless Electric Buying Guide

    Ecosmart Tankless Water Heater

Info & Guides

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Assembled Depth (in.)  14.0 in  Assembled Height (in.)  18 in 
Assembled Width (in.)  4 in  Product Depth (in.)  14 
Product Height (in.)  18  Product Width (in.) 
Water Connection Size (in.)  3/4 In. NPT 
Amperage (amps)  75  Electric Product Type  Commercial & Residential 
Finish Family  White  Flow Rate @ 35 F Rise (gallons/min)  3.5 gal (US)/min 
Flow Rate @ 45 F Rise (gallons/min)  2.72 gal (US)/min  Fuel Type  Electric 
Indoor/Outdoor  Indoor  Maximum Temperature (F)  140 
Minimum Activation Rate (gpm)  .25  Minimum Temperature (F)  80 
Point-Of-Use  No  Product Weight (lb.)  11 lb 
Residential/Commercial/industrial Use  Residential, commercial or industrial  Returnable  90-Day 
Water Connection Location  Bottom  Water Heater Features  Wall Mountable 
Wattage (watts)  18000 
Warranty / Certifications
Certifications and Listings  1-UL Listed,CSA Listed,ETL Listed  ENERGY STAR Certified  No 
Labor Warranty  No Warranty  Part Warranty  Lifetime 


Rated 4.3 out of 5 by 57 reviewers.
Rated 5.0 out of 5.0 by Works Fine. Unit was installed by Licensed Electrician and Plumber. Works well so far. Takes up less space than the old tank and I`m looking forward to many years of use. Unit was Pre-tested before shipping for leaks and power problems,I like that. September 16, 2014
Rated 5.0 out of 5.0 by It does what it says it will... After much research, I chose this unit due to the amprage and wiring needed. The bigger unit would of been preferred, but limited space in electric panel for an addition double breaker and the additional guage wire and number of wires required. I was a little skeptical if this unit could meet my needs, but after installation completed I was able to confirm a 76 degree rise in temp (10ft away) and 66 degree rise in temp (over 150ft away from unit) running a lavatory faucet and a shower. Installation was easy once wire run to unit from panel (approx 50ft). Incoming water temp was 44 degrees from a deep well in Southwest MI in April when install completed. April 22, 2014
Rated 4.0 out of 5.0 by Efficient Hot Water Today I called the gas company and shut off my service. My old 40 gallon water went out on me 10 days ago. I ordered this 18KW ECO SMART system when it was on sale for 319.00 So far everything works GREAT! The biggest concern you will need to address is you breaker box in your home. If you have a 150- 200 AMP breaker box don't think twice about getting this. I had to have a good bit of ELECTRICAL work done to upgrade for this system. I researched the many options out there. This was what I was looking for. Something that was 100% electrical, On demand use, Self contained, and almost no maintenance for up keep. My brother and I put ball valves in the lines to ease the maintenance and service for the Eco Smart system. It handles with EASE a nice hot water temp in my upstairs master-bedroom shower. This is the farthest point away from the unit. All and all I am very happy so far with this investment for my home. December 11, 2013
Rated 2.0 out of 5.0 by Good product, disapointed in warranty Nice product. I was disappointed by manufactures limitation on warranty. The instructions state installation must be performed by licensed plumber & electrician or warranty will be voided. When I purchase product from Home Depot, I expect to be able to install myself. I did install the product on my own, it looks & works great, but now concerned if I have a manufactures defect, ECO will not cover it. January 20, 2015
Rated 4.0 out of 5.0 by before u by make shore u have enough brraker room or u will end up buyin piggy back breakers that will cost u 25$ apiece Love it just make sure u have plenty of room in breaker box or u will have to buy piggy back breakers at25$ a pop September 17, 2013
Rated 5.0 out of 5.0 by Pleased Had replaced a similarly spec'd Bosch tankless elec water heater that failed due to notorious controller board failure just after warranty expired. This EcoSmart provides more consistent hot water flow than the Bosch did and it's worked flawlessly for over a year now. Was easy to install, but hookups from Bosch were already present, making job easier. Previous and new plumber have both been skeptical that these units could provide hot H20 for master bath/shower, master sink, and guest bath sink, but it does it easily. Having LED temp readout and easy access temp control knob also nice. I'm buying another one for the guest house bath. Some saying install difficult, but I can't see this as being anymore difficult to install than any other tankless water heater. Each might require new electrical circuit and plumbing, so should be no surprises there. October 4, 2014
Rated 5.0 out of 5.0 by Happy with Purchase of ECO 18 KW Tankless Water Heater Water Heater was exactly what I expected since I already owned an ECO 11 and ECO 27 which I have installed in different properties that I own. The water quickly heats up and the unit is very nicely built. I would recommend purchasing one of these if you need space or just want to save money on your energy bill. February 17, 2015
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