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Rheem EcoSense

Model # RETE 18

Internet # 202514585

Store SKU # 452888

RETE-18 - 18KW 2.73 GPM Electric Tankless Water Heater

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

$379.99 /each
  • Uses energy only when hot water is needed
  • Compact design allows simple installation almost anywhere
  • On unit control allows for easy temperature adjustment


Model # RETE 18

Internet # 202514585

Store SKU # 452888

Store SO SKU # 1000114408

The Rheem EcoSense RETE-18 tankless Electric Water Heater features a rugged brass and copper heater exchanger that is designed to withstand tough water conditions for long life. Its lightweight and compact design enables simple installation in a variety of locations. It is designed to provide hot water for up to two bathrooms in warmer climates or a single bathroom in colder climates. Please click the “More Info” Tab and then “Specifications” to view the Rheem Brochure Guide to assist you in your purchasing decision.

  • Provides a maximum of 3.51 GPM continuous flow at a 35 degree Fahrenheit temperature rise
  • Designed to provide hot water for up to two bathrooms in warmer climates or a single bathroom in colder climates
  • Flow rate provided by a tankless electric water heater is dependent on the difference in temperature of the incoming cold water supply and the desired hot water delivery temperature
  • 18 kw water heater requires a 240 volt electrical service, 2 separate 40 amp breaker(s) and 8 gauge copper wiring
  • Energy efficient, uses hot water only when needed
  • On-unit temperature controls and LED lights indicate active elements and system operation
  • Modulating control adjusts power consumption to meet the required hot water temperature and flow rate
  • Rugged brass and copper heat exchanger is designed to withstand tough water conditions for long life
  • Lightweight and compact design saves space and enables simple installation in a variety of locations
  • Requires 240 Volt Electrical connection
  • Equipped with ½ in. water connections for easy installation
  • Modulating Control adjusts power consumption to meet the required hot water / temperature flow rate

    How to Choose Your Rheem EcoSense Tankless Electric

    Choose your application, ie. shower, bath tub or vanity sink-faucet, kitchen sink faucet or washer. See chart below.

    For example: you choose a kitchen sink faucet.

    See application chart below and locate your flow rate. For example: your flow rate is 1.5 gpm.

    On the map, locate the average water temperature in your area.

    For example: your water temperature (in Atlanta) is 55°

    Use the water temperature and flow rate chart to determine the model you need.

    For example: 1.5 gpm flow rate + 55° = RETE 9.

Info & Guides

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Product Depth (in.) 
Product Height (in.) 
Product Width (in.) 
Water Connection Size (in.) 
Amperage (amps) 
Electric Product Type 
Point of Use 
Finish Family 
Flow Rate @ 35 F Rise (gallons/min) 
Flow Rate @ 45 F Rise (gallons/min) 
Fuel Type 
Maximum Temperature (F) 
Minimum Activation Rate (gpm) 
Minimum Temperature (F) 
Product Weight (lb.) 
12 lb 
Residential/Commercial/industrial Use 
Residential or commercial 
Water Connection Location 
Water Heater Features 
No Additional Features 
Wattage (watts) 
Warranty / Certifications
Certifications and Listings 
2-UL Recognized 
ENERGY STAR Certified 
Labor Warranty 
No Warranty 
Part Warranty 
1 Year 


Rated 3.5 out of 5 by 56 reviewers.
Rated 1.0 out of 5.0 by Poor Quality - works for 2 years tops!!! The first one I bought was DOA (red flag) and got this replacement ordered on 6/19/12 at Home Depot in Hurricane, WV. It was installed around August 2012 and it died right after Thanksgiving 2014. So about two years or less is all your going to get out of one of these. I haven't seen where anyone has had one longer than that. So I guess I was lucky. It was in a detached two story garage with a full bath and I bet it didn't have 1000 gallons through it. The board on these are extremely fragile. Remember only 1 year warranty. Should have done my homework before I bought this unit or paid attention to the red flag. Guess I will go back to tank heater. Even the other brands have similar problems. February 5, 2015
Rated 3.0 out of 5.0 by Great Performance, Poor Reliability I bought this unit to replace a standard water heater that leaked and caused major damage. First, for any tankless unit, there are hidden costs, unless you do the extra work yourself. Tankless electric heaters draw a lot of current, and this unit uses two 40 amp breakers. Unless you have these near your water source pipes, you will have to run power from your breaker box to where the water heater will be located, cost: $700+. Water lines must also be configured to rise vertically and turn 90 degrees to be connected on the sides of the unit, cost $500. I used this unit for almost a year, and it performed well for a home with one bath/shower. Then a few days before the 1 year parts warranty ran out, it quit making hot water. A professional plumber diagnosed the problem as being a failed flow regulator, and the unit's design meant that the whole heater had to be replaced. I received a new unit free of charge, and had it professionally installed. Six days later, the hot water suddenly dropped off to luke warm, and yet another professional diagnosis was required (all of which costs a minimum of $89 per call). The verdict is that one of the two heating units in this product failed, and the unit is now operating at half power. I am now faced with removing the unit and sending it back a 2nd time, but I am becoming skittish about the reliability of the product. When it goes down, I spend at least a week without hot water, and I expected this product to last ten years, but so far, I can't get even one year out of two heaters. I'm going to get a third one because I don't want to have to reconfigure the water lines for a different brand, but if a third unit fails, I will switch brands anyway. This is a great product--when it works--but long term reliability is an issue in my experience. August 8, 2012
Rated 4.0 out of 5.0 by Super Hot Water! Our house is under construction and needed something small and electric. The unit works great and the water is scalding hot! The shower has endless hot water but I don't recommend using the hot water in sink at same time as shower (shower gets cold). Because of it's size it was perfect for our application. This is a huge energy consumer while operating and your lights will dim and possibly flicker. It uses 2 dedicated 40 amp breakers and 2 runs of 8 AWG wire. I would have given this 5 stars for it's awesome heating power, however was a little disappointed that none of the pex fittings would just hook right up. It uses a 5/8 compression fitting and requires a little creativity and reducers to keep it in a small compact area. December 9, 2014
Rated 1.0 out of 5.0 by do not buy you cannot get parts for this item the water heater is only one and a half years old the company will not warranty the electronic board. and you cannot buy a replacement board you have to buy a complete water heater for $500. electronic boards probably only worth $75. really bad company for not caring replacement parts February 6, 2015
Rated 5.0 out of 5.0 by Great product It delivers endless hot showers and see no difference on waiting for hot water vs. my old tank type heater. I like the maintenance free by having an electric unit. The electric hookup is designed where you can run on 2 separate breakers but I ran #6 wire (100 feet) on one 70 amp breaker and works just fine. The unit arrived in 3 days. June 12, 2013
Rated 4.0 out of 5.0 by Was very happy with my tankless system I have had my tankless hot water for 4 years and never had any problems till now due to the hard water in my area. I will buy another but this time will add a descaler or an ion exchanger to help with the quality of the water. May 13, 2015
Rated 5.0 out of 5.0 by Tankless doing it's job Replace a 50gal electric with this tankless. As advertised, you will need electrician to install the 220 line. Don't try this yourself. From a Cold start, it takes less than a minute ( 30 sec) to get hat water to the kitchen sink. This is a small (1000 sq ft ) redo DIY house that is being renovated, so this should be more than enough. With the 50 gal, we were shutting off the water heater every time we left for a couple of day. We did the plumbing( with help of old retired plumber to help) and hook up was a snap. Again, make sure the electrical is done right, as this is a 220 line and it will use power. No instruction were included, but it was not hard to figure it out. Cold line goes to cold intake, etc. January 6, 2015
Rated 1.0 out of 5.0 by They quit working after about a year. On my second unit and it just went out. Same thing as before. The switch that activates heating the water stops working. My first one went out just under a year so was under warranty, but my new unit is at about 1 year and went out again. To discouraged to even try to warranty. switching brands. I will never buy Rheem again. And will push other brand to friends and construction industry coworkers. November 6, 2014
  • 2015-09-02T11:04:18.010-05:00
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