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Rheem

Rheem 240V Heating Chamber RTEX-13 Residential Tankless Water Heater, GRAY

  • Based on 1,345 reviews
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Availability: In Stock.
Fulfilled by Amazon
Arrives Thursday, Apr 30
Order within 9 hours and 49 minutes
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Features

  • External adjustable digital thermostatic control with LED display (+/1 degree accuracy
  • Durable Copper immersion two heating elements, field Serviceable.Self-modulating power control
  • Simple installation 1/2 NPT adapters included; side 1/2 inch Compression water connections
  • 99.8% energy efficient. External controls to adjust temperature in increments of 1f. Water-Saver Shower Head 1.5 GPM
  • Threaded for easy replacement, simple installation, digital temperature display 54 A. 13kW Model Flow Rate: up to 3.17 GPM
  • 54 A

Description

Professional classic® tankless electric water heaters offer continuous hot water quick and on demand for single point-of-use or multiple applications

Brand: Rheem


Capacity: 1.5 Gallons


Power Source: Electric


Product Dimensions: 8.25"W x 12.62"H


Special Feature: LED Display


Power Source: Electric


Special Features: LED Display


Wattage: 13 KW


Voltage: 240 Volts


Flow Rate: 4.8 Gallons Per Minute


Maximum Temperature: 140 Degrees Fahrenheit


Heat Output: 13 Kilowatts


Efficiency: at least 99.8% energy efficient


Mount Type: Wall


Is Electric: Yes


Color: Gray


Style Name: Heater


Material Type: Copper


Capacity: 1.5 Gallons


Item Dimensions W x H: 8.25"W x 12.62"H


Item Weight: 1.8 Kilograms


Item Depth: 0.5 inches


Brand Name: Rheem


Model Number: RTEX-13


Manufacturer: Rheem


UPC: 020352685328


Global Trade Identification Number: 28


Manufacturer Part Number: RTEX-13


Included Components: Rheem RTEX-13 Residential Tankless Water Heater


Unit Count: 1.0 Count


Item Type Name: Rheem RTEX-13 Residential Tankless Water Heater


Frequently asked questions

If you place your order now, the estimated arrival date for this product is: Thursday, Apr 30

Yes, absolutely! You may return this product for a full refund within 30 days of receiving it.

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Top Amazon Reviews

    • Flintstones to The Jetsons.
These systems are amazing. The future is in your hand when you hold one. I fully recommend. Please, however read on to understand them better. Customer support is awesome and available. This 13kw unit worked in my home I went thru two of the 18kw units that would not work. Please read on. You will want one and never look back. These WH’s are complicated. They work awesome in the lab environment they were created in. If your home does not match that lab setting or you can’t recreate it. It will not work. I went thru three of them. YOU WILL NEED. Flow restrictions, preasesure regulators, water softener, filters(?), and a lot of patience tuning it to work. Once tuned however, they are flawlessly perfected at heating water instantly. Wow! the future is in these devices. Why was mine so difficult? I’m the last house from the power company. Literally at the end of the line. And I put in the 18kw unit. They are all super easy to install in both wiring and plumbing, but, what appeared to be my problem was there wasn’t enough physical energy to run it properly. Duel 40 amp req. So it wouldn’t work unless the flow restriction was almost closed. I tweeted and tweeted every possible measure to get it to work. I’m on well water so that incoming cold temperature affects the system and set up on a 40/60. The water rate It was moving was to fast and I never could get both sides of the water heater on. It just would NOT work. It would come on for a sink at half open but when you tried to shower. It would turn off and say E5. Oh how I grew to hate that display. A simple to read display and simple to adjust temperature dial. I literally went from Flintstones to The Jetsons in appearance. About this 13kw unit. WHICH SOLVED MY PROBLEM. It’s a little more than half the power necessary to function. Single 50 amp It is doing its job beautifully now. I have almost full water pressure again and it seems sold at 130 deg. But again, several hours spent tuning so it did work. If the flow rate is to high and water temperature to low it will not work. You have to tune them with additional devices to stabilize them so that units performance in the lab environment it was created in and it needs. I have replaced two tanks now. One electric in a home and one propane in a camper. Worth it! ... show more
Reviewed in the United States on December 6, 2025 by Biz Trailer
    • Game Changer
We installed the Rheem 240V Heating Chamber RTEX-13 Tankless Water Heater, and it has completely transformed our buildings hot water system! Pros: Endless Hot Water: This unit provides a continuous supply of hot water, which is perfect for our busy buildings. No more waiting for a tank to refill! Energy Efficient: The on-demand heating means we only use energy when we need hot water, resulting in noticeable savings on our utility bills. Compact Design: Its compact size allows for easy installation in tight spaces, which is a major plus in our buildings. User-Friendly Controls: The digital temperature display and adjustable settings make it easy to customize the water temperature to everyone's liking. Reliable Performance: We’ve had no issues with temperature fluctuations, and it maintains a consistent flow even during peak usage times. Overall, we highly recommend the Rheem RTEX-13 for anyone looking to upgrade to a tankless water heater. It’s efficient, reliable, and has made a significant difference in our daily routine! ... show more
Reviewed in the United States on October 1, 2024 by Speed Global Services
    • Works great - learn how to clean with no purge valves
Installed this--my first--tankless water heater 3 years ago. Just my wife and I in a 2 bath home in south Florida (warmer entering water temp than most of US). Been very pleased. Endless hot water with steady temps and no issues with competing hot water demands such as dishwasher, sinks, etc. I've been surprisingly satisfied. A few weeks ago we started noticing a drop in water pressure and some temperature fluctuations. Honestly, though I am reasonably handy and experienced, I had no idea I should be cleaning the heater annually. Long story short - cleaned the unit and everything is back to normal. More detail for those who, like me, had the water heater installed without purge/diverter valves. I had only copper piping and no way to flush the heater. Read about some people who used a plumbing circuit involving a washing machine, but couldn't see that working for me. So, I went to Home Depot and spent about $170 on a purge valve kit, copper fittings, pipe, solder, flux, etc., ready to re-plumb my water heater and install purge valves. As I removed the compression fittings attaching the copper pipe to the heater I thought, "why don't I just attach hoses directly to the unit and skip all the plumbing?" That's what I did and it worked beautifully. In my case, I purchased 10' of clear plastic tubing, cut it in half and attached to the heater with band clamps. Used a 1/4hp pump in a 5 gallon bucket and flushed the tank for around 60 minutes. I changed the direction of the flow at about 30 minutes, not sure whether or not it helped but seemed a good idea. Returned almost everything I bought for the project, went home and took a nice long hot shower. ... show more
Reviewed in the United States on June 7, 2024 by gcp

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