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Rheem

Rheem RTEX-24 24kW 240V Electric Tankless Water Heater, Gray

  • Based on 2,977 reviews
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Availability: Only 3 left in stock, order soon!
Fulfilled by Columbiatradestock (S/N Info Recorded)
Arrives Tuesday, Jun 9
Order within 14 hours and 4 minutes
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Style: Whole Home, 24 kw


Features

  • ELECTRICAL REQUIREMENTS: 3 x 40 AMP Double Pole Breakers Required. 200 AMP Household service recommended. Ensure your home can accomodate the power supply and that enough space is available in your breaker panel for this unit. RTEX-24 model is 100A, 24kw, 240V.
  • PROVEN PERFORMANCE: Continuous hot water when you need it for the whole home (review performance guide image to confirm this water heater will provide the hot water needed based on geographic location). Ground water temperature impacts temperature rise and gallons per minute.
  • EASILY ADJUSTABLE: ON/OFF Dial Control with adjustable digital temperature display allows for adjustments in 1-degree increments from 80-140 degrees F.
  • EFFICIENT: Tankless electric water heaters save space, energy, money, and require no venting.

Description

The Professional Classic Tankless Electric RTEX-24 240V is engineered to provide continuous hot water on demand, making it ideal for both single point- of-use and multiple applications, with a remarkable flow rate of 5.9 GPM. Its compact design is up to 93% smaller than traditional electric water heaters, allowing for significant space savings, while its energy-efficient operation eliminates standby heat loss when installed near the point-of-use. See performance guide for average expectations in your region based on ground water temperature and application usage. 3 x 40 AMP Double Pole Breakers Required. 200 AMP Household service recommended. Ensure your home can accomodate the power supply and that enough space is available in your breaker panel for this unit.

Brand: Rheem


Capacity: 5.9 Gallons


Power Source: Corded Electric


Product Dimensions: 17.63"W x 18.25"H


Special Feature: LED Display


Power Source: Corded Electric


Special Features: LED Display


Wattage: 24 KW


Voltage: 240 Volts


Flow Rate: 5.9 Gallons Per Minute


Maximum Temperature: 140 Degrees Fahrenheit


Heat Output: 24 Kilowatts


Efficiency: 99.8% Energy efficient


Maximum Pressure: 150


Mount Type: Wall


Is Electric: Yes


Maximum Pressure: 150 Pound per Square Inch


Capacity: 5.9 Gallons


Item Dimensions W x H: 17.63"W x 18.25"H


Item Weight: 17.8 Pounds


Item Depth: 3.5 inches


Material Type: Stainless Steel


Brand Name: Rheem


Model Number: RTEX-24


Manufacturer: Rheem


Manufacturer Warranty Description: Limited lifetime warranty


UPC: 020352685397


Global Trade Identification Number: 97


Manufacturer Part Number: RTEX-24


Included Components: Fittings, Aerators


Unit Count: 1.0 Count


Item Type Name: Water Heater


Color: Gray


Style Name: Whole Home, 24 kw


Frequently asked questions

If you place your order now, the estimated arrival date for this product is: Tuesday, Jun 9

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

To initiate a return, please visit our Returns Center.

View our full returns policy here.

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Top Amazon Reviews

    • Tankless Hot Water install
Style: Whole Home, 24 kw
I replaced a 55 gallon hot water tank with this unit, I bought a little larger unit than what the ratings said I needed to be safe. Make sure you check your electrical panel to make sure you have room for 3 x 40 double pole 40 amp circuit breakers. I didn’t have enough room, had to add a sub panel plus had to run 9 x 8 gauge wires the unit requires. I’m pretty handy, but asked a certified electrician to help me with the pre wiring. To be honest, I would have been afraid to try and do this myself even with all my experience. Installation was pretty simple after you have the wiring installed. Use 1 inch piping from your electrical panel to the tankless electrical unit or you won’t be able to pull the nine 8 gauge wires through the pipe. I also suggest having an electrical panel with a main breaker so you don’t have to shut the whole house down for the final install. Additionally i installed a surge protector to hopefully protect the unit from power surges which appears to have delicate electronics inside. We’ve only had this unit in operation for 4 days so far, but the water is really hot, have had no issues at this point and I love the added space gained without having the tank. Time will tell if we save 50% on energy, but from all my research it makes sense even with us living in a warm climate. There are several tankless unit manufacturers with great ratings, I went with Rheem because if I have an issue, they are based in the USA and hopefully that means English speaking in my time zone….. Hope my review is helpful to you. Update: it’s been 7 months, still works great, very happy with this decision even though I can say I’ve seen significant energy savings ... show more
Reviewed in the United States on May 6, 2025 by Amazon Customer
    • Easy install
Style: Whole Home, 24 kw
Great quality
Reviewed in the United States on April 8, 2026 by Emily
    • Easy installation. Works well.
Style: Whole Home, 24 kw
Review Image by K.Barron
Just installed. Works well. Hope it will last longer than the off brand one we had before. Very easy installation due to being a replacement for the same style unit. Electrical, plumbing and mounting locations all the same.
Reviewed in the United States on March 29, 2026 by K.Barron
    • Hot Garbage
Style: Whole Home, 18 kw
New Review: Ok, this lasted 26 months before I finally ripped it off the wall and replaced it. It had failed three times in that 26 months, and this was the last straw for me. After almost exactly one year, one of the heating elements fell apart. It was literally in pieces. I replaced the bad element with a third-party element, and almost exactly one year later, the second factory heating element fell apart, too. My water has very low mineral content, but after the first one failed, I cleaned the elements every six months along with flushing the whole system. That still didn’t keep the factory elements from failing. The third-party elements looked fine. I bought some spares just in case. Finally, last weekend I started noticing that the water coming out of the tap was CRAZY hot. When I started looking for the problem, I found that one of the heating elements was stuck on all of the time. The water would just keep heating up inside until the thermal protection circuit turned it off. Something in the electronics had failed. There was another issue with the water heater unrelated to these failures, too. I have solar panels on my roof, and I found that whenever someone would turn on the hot water, the solar inverter would turn off. The water heater was injecting too much electrical noise onto my power lines, which the inverter didn’t like. There is absolutely zero electrical noise filtering on the water heater, so I added my own. This fixed the solar problem, but the filter that I added consumed some power all of the time, so it wasn’t saving me energy like I’d wanted. I replaced it earlier this week with a 24kW model from a different manufacturer thar I found locally. The new one, even though it has a higher power rating, uses nearly half of the energy required by the Rheem to take a shower, 7kW vs 12kW. Since it has a higher power rating, it’s easier to use hot water at multiple points simultaneously. It also has a dynamically adjusting flow meter, compared to the Rheem where I needed to add an external flow restrictor. Don’t buy this heater. Spend a few dollars more and get something that is built better, doesn’t constantly break down, and doesn’t cost as much to operate. Get a Stiebel Eltron Tempra 24 Plus, which costs a bit more up front, but works much, much better. Original Review: A week shy of one year ago, I purchased this to replace the old water heater in my home that had quit working. The installation was easy, it only took me an hour or so to swap out, and it worked great. For a year. My warranty will expire in three days, and the water heater stopped working a few days ago. It wasn’t completely dead, and it would heat the water to around 85 degrees, but that still makes a miserable shower. I called the warranty department, and they sent me a troubleshooting guide. Using this guide, I determined that one of the heating elements was open. Honestly, I didn’t feel like it was worth the effort of trying to get this fixed under warranty, so I ordered a replacement (two, so I could replace them both) 9kW heating element here on Amazon and they were delivered the next day. The maintenance instructions say that you should pull the elements out every 6-12 months and soak them in vinegar to remove any scale, but admittedly, I hadn’t done that. My water is very soft with a low mineral count, so I tend to neglect things like this. When I removed the bad element, there were no mineral or calcium deposits on it, but the element was in horrible shape. It was all burned up, with gaping holes, twisted metal, and exposed, broken metal coils. The other element looked perfect. The bad one looked like it had been in a furnace. I replaced the elements with new ones, and it’s operational again. I’m happy with this heater while it is working, but I don’t know if I’m crazy about possibly needing to replace the elements once a year. Hopefully, I just had bad luck with the one element. ... show more
Reviewed in the United States on March 20, 2022 by ES

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