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Rheem

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

    • Based on 1,170 reviews
Condition: New
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$315.00 Why this price?
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Availability: 20 left in stock
Fulfilled by Amazon
Arrives Saturday, May 4
Order within 16 hours and 5 minutes
Available payment plans shown during checkout

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


Product Dimensions: 8.25"W x 12.63"H


Special Feature: LED Display


Color: Gray


Wattage: 13 KW


Brand: ‎Rheem


Product Dimensions: ‎8.25"W x 12.63"H


Special Feature: ‎LED Display


Color: ‎Gray


Wattage: ‎13 KW


Voltage: ‎240 Volts


Heat Output: ‎13 Kilowatts


Manufacturer: ‎Rheem


Part Number: ‎RTEX-13


Item Weight: ‎0.01 ounces


Item model number: ‎RTEX-13


Is Discontinued By Manufacturer: ‎No


Thickness: ‎1 Inches


Item Package Quantity: ‎1


Special Features: ‎LED Display


Included Components: ‎Rheem RTEX-13 Residential Tankless Water Heater


Batteries Included?: ‎No


Batteries Required?: ‎No


Date First Available: January 19, 2017


Frequently asked questions

If you place your order now, the estimated arrival date for this product is: Saturday, May 4

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

    • An excellent Rheem product!
I paid about $240 for this unit, servicing a 1300 sq ft cabin with 1 full bath, a half bath, dishwasher, washer and a kitchen sink. Item works extremely well, water gets hot in bathroom almost instantly, the unit in in basement below bathroom. Kitchen is about 20 ft away on first floor and it takes about 45 sec to get fully hot. Upstairs bathroom gets hot in about 2 minutes being furthest away and having a long run of pipe to get to. I did all the labor myself and put in a 60 amp breaker in my panel and it cost about $500 total with parts. The 6/2 romex wire cost about $150 for 50 ft so that was priciest part aside from unit. If you have any sort of building ability just put it in yourself and save the $$. All it needs is connected to water lines and the wire run from panel to the unit, it takes 2 hot wires and a ground (240v, all the power gets dumped into the heating element so no return voltage with neutral wire). I replaced an 80 gallon Rheem electric tank heater that was almost 30 years old and working fine until I flushed the tank and probably broke rust off the heating elements so it started tripping the breaker constantly. I am now saving a ton of electric costs in not having to heat 80 gallons of water for a smaller home that doesn’t need that much. I noticed if you run the shower, washer and dishwasher at same time the temp will cycle between hot and colder water in the shower because it can’t handle that many high flow items at same time. A shower and dishwasher or shower and washer at same time no problem however. I can’t recommend this unit more, I tell people about it all the time! Great value for money, especially if you install it yourself. Just follow directions to the letter and make sure you use proper breaker types in your panel (QD vs QO, etc). ... show more
Reviewed in the United States on September 6, 2021 by Michael Krimm
    • this is about an inch bigger than the earlier model
this was a pretty easy replacement for the previous unit which had corroded inside and failed to provide any hot water. The price seems right and they seem to work OK. This is in a rental apartment. I might consider them for a vacation home. One minor boo-boo occurred in which i adjusted the output pipe links to the new plumbing to account for a valve that I wish to add in. My calculation was good but I failed to measure the new unit which was about an inch wider than the previous one. ... show more
Reviewed in the United States on August 29, 2023 by Chris Stratton
    • Great Heater!
Had to return because there was no way to drain water from tank to prevent freezing. I did return it.
Reviewed in the United States on December 9, 2023 by David M Zalikowski
    • Does Its Job Pretty Well So Far!
Review Image by Mike W Mike W
Review Image by Mike W Mike W
Review Image by Mike W Mike W
So I needed something that would give me constant and consistent Hot Water for the kitchen sink and the dishwasher. I wanted it accessible but not visible. After much research, I settled on the Rheem 240V Heating Chamber RTEX-13 Residential Tankless Water Heater. After approximately one year of service use, I can say this has been a really good purchase so far. Produces hot water 'almost' instantaneously and keeps a pretty constant and stable temperature once its left running for a bit. If you start using hot water, then stop using it, and then start up abruptly again, you should be a little cautious because that second wave of hot water is going to be hotter than your original setpoint as the heater hasn't had enough time to dial back the temperature yet. But this isn't a problem with this unit, it's an issue with all these types of small electric water heaters. But even with this, it's a small issue and if you wait a few seconds then its no issue at all. Now I have noticed that in the last few months, it's taken a little longer for the water to get up to temperature. I think this has something to do with deposit buildup within the unit. I'll have to figure out how to flush it, which is usually standard maintenance for any water heating unit. But even now, that's a few extra seconds and then she's back to normal. We haven't had any real problems in the year we've used it. It keeps up really well with the new dishwasher we've bought too. All in all, this is a pretty good unit, and does its job very well. ... show more
Reviewed in the United States on June 1, 2023 by Mike W Mike W
    • So far so good
Rheem 240V Heating Chamber RTEX-13 Residential Tankless Water Heater, GRAY Delivered Nov 11, 2021 TLDR: It's all about the GPM About 2 months in and no problems so far. This is my 1st tankless and quite happy with it. Doesn't take any longer to get hot water than it did with the tanked one. A few seconds depending on which side of the house you're on and a moment to settle as the pipe it's traveling through warms up. I was a little on the fence about the wattage and really didn't fancy needing two 240 lines for the next size up, but this did the trick. I've read some stuff saying 13kw wouldn't be up to the task of a hot shower in the northern states but took a chance and it's working just fine. That being said if the GPM is too much it wouldn't keep up, but it's more than enough for a very hot shower at just over 1 GPM, maybe 1.5 GPM total flow. It will do just under 1 GPM scalding injury hot with no cold water mixed in, somewhere between 1~1.5 GPM total flow with a little cold water in the mix for extremely hot shower hot. Some data to clarify... In PA just north of Philly, currently mid January and it's been pretty cold, 20 degrees most nights recently but it's dipped to 10, and I'm on frigid cold well water, and getting a hot shower I still need to mix in a some cold water or it's hot enough to burn you. So plenty good. Hot water heater to shower is roughly a 40~50 foot run through 3/4" pex in an unfinished unheated basement then down to 1/2" copper right at the bathroom and I get just under 1 GPM with the hot water valve wide open (after some previous adjustments to the flow rates on the feed lines)... 1 gallon in 1.18 minutes whatever that equates to. Now I did meter the hot water to everywhere but the washing machine via valves in the basement a few years back and that's working to my advantage now. I was dealing with an annoying ex-girlfriend who would run the hot water wide open and act like there was a problem with the heater or plumbing when she used up 40 gallons of hot water in under 10 minutes (with the tanked unit), or the water wasn't getting hot enough while she was blasting 4 GPM of cold water. And her disdain for logic and reason necessitated me finding a way to idiot-proof the situation. So my system is capable of delivering water much faster. Keep in mind I have a septic system as well so all this ridiculous water use was going into the back yard ready to overload my leech field. But regardless my typical routine (even when I had the tank unit and doing the same now) is open the hot water valve a little more than half way, give it a sec to get up to temp, then mix in just enough cold water so it's not going to put me in the burn ward. If you think I don't like hot showers it's hot enough to turn my normal Scottish pallor red and steam up the bathroom like a sauna. BUT it's not some kind of deluge GPM-wise, and I've adjusted the water like I have a functioning brain. Bathroom shower, sink, and kitchen sink will get hot enough to be steaming and scald you with the hot water valves full open which is (adjusted to) around 1 GPM +/- . And also the washing machine, which has not been throttled in any way, does not get fully hot. It could if I metered the hot water a little bit but I'm up in the air on steaming hot water in the washer but it taking a little longer, vs. just leaving it as is with warm water and it finishing quicker. Anyway, too many GPM and the 13kw heater can't heat it fast enough to keep up. But it does a more than acceptable job, even in PA winter, if you're not a glutton with the water. If you need to use more than one fixture at a time and expect more than lukewarm water, especially if one of them is a shower, this is likely not gonna cut it by itself. If you have a very high flow situation like a waterfall or rain type shower head, and/or have one of those stupid single handle valves that doesn't give you any indication of how the hot and cold are being mixed, and/or you have people who can't process mixing the hot and cold water in a sense-making way, you may want to go a step up to at least 18kw or more for full house, or maybe a 13kw main and another small one right at the bathroom to boost it. If you can live with just under 1 GPM scalding hot water, just over 1 GPM mixed hot water for a shower, 2 or 3 GPM of warm water, then you should be ok with 13kw. If I was to have one complaint with this unit it's that it needs too much flow before it kicks on. For example if I just want to wash my hands real quick and don't want ice cold water and don't need tremendous water flow, my typical opening of hot and cold valves like a quarter turn wont be enough flow to trigger the hot water heater to kick on. It won't come on till the hot water valve gets close to halfway open. Haven't looked into if that's adjustable or not but don't believe it is. Aside from that build quality is about what you'd expect these days, and by that I mean marginally acceptable at best. I really like the stainless heating tubes, being that I have acidic well water, but I have a feeling they're probably 304 rather than more corrosion resistant 316. And they screwed up corrosion resistance putting failure prone (when it comes to acidic water) brass in the mix anyway. But end to end 316 stainless units don't exist to my knowledge. "We can't design things for extreme cases like acidic or hard water!" ... Yes you can, very easily, you just want to make disposable crap so we need to buy more. Could you imagine buying one of these that would last forever no matter your water type and just having to replace the elements and flow sensor every few years, maybe clean some scale out of it if you had a lot of minerals? And some of the comparable units had copper tubes which would be far worse than 304 and brass, so not bad for what's available. And one thing I love about these is they are so small and light and now that the wiring's re-done it will be a breeze to swap out in a few years once my water eats it up. No more pumping out a 40 gallon tank and humping the heavy pieces of crap in and out of my basement :) And I feel I should qualify I'm really not some kind of water conservation nut. It's just most of my life having wells and septic systems you're much more in touch with where you're water's coming from and where the waste is going. It's great to have no water or sewer bills and be self sufficient, but I'm responsible for them, and both are expensive nightmares with direct and immediate impact if something goes wrong. It just makes sense to use what you need and respect the system. No water source is limitless and waste doesn't just magically disappear. ... show more
Reviewed in the United States on January 23, 2022 by Bob Dawson

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