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

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!

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!

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.

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.

I wasn’t 100% sure how well this little tankless heater was going to do with how cold my water was, but reading The other reviews I felt confident it Might work. It’s just right with the right showerhead I turn the shower full hot. Wait for a minute or two and get in. It keeps perfect temperature no fluctuations I would definitely buy again. I have already recommended it to another friend that was building a cabin as well and did not want to sacrifice space for a large water heater. I have been buying product from Amazon when they were only selling books and I’ve never left a review, but this one deserved it. Do yourself a favor and buy High Sierra Showerhead 1.25 GPM it works perfect. It’s a bit expensive but it’s top quality and is worth it you won’t believe how well it is made. I bought the handheld unit, and just bought a second one for my upstairs bathroom.

I love this product when it works. Unfortunately, it seems to have a lifespan of about 2–3 years, after which it simply stops heating water. If you decide to buy this unit, make sure you also purchase the warranty, because dealing with customer service is a hassle. Be prepared to act like an electrician — they’ll have you pull out a multimeter and walk through a full service check. Most people don’t have 30+ minutes to troubleshoot an appliance or learn electrical testing just to be told the unit has failed. I’ve purchased four of these units. The first was bought in August 2020, and now I’m already looking at replacing the most recent one, purchased in November 2023. At this point, I’m exploring other options.

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.

I knew about tankless water heating for a long time, but I replaced over half my flooring last summer, and when I looked at the area for my old water heater, I decided to make the transition to tankless. It is all it should be. Water stays completely the same temp, even when on long periods of time. Works perfectly, but time will be the test. Biggest advantage otherwise? the costs savings. My electricity bills have dropped around 30% per month. The unit should pay for itself in the first year. I installed it myself, and it's an easy one to do. Sharp looking too; looks great on my utility wall. ONLY down side: Rheem has NOT put this model in for the 'Star Energy' certification, so when I put in for the 'green' rebate with my Electricity Utility, they turned it down. But the product itself, I can only brag on up 'till this point. I only have the one for the whole home, but I were building a new one, I'd put one individually on each faucet for even better performance and cost savings.

Works very well. Replaced older model that did not have variable temp control. If you are in a cold climate, this will not keep up for high flow taps like your tub. However, living on a dug well in southern/central Ontario, this has been adequate as the main water heater. We have 2 low flow shower heads in one shower and you can turn both on and never run out of hot water. Not sure about energy savings as it is hard to calculate as I work weekly rotating shifts and my water usage is at different times of the day which equals different rates.

We did hire an electrician and a plumber to be on the safe side and to get it done quickly. This works with our 100 amp service as we are also efficient in our electrical needs and uses. We are only 2 in our household. Our kitchen sink is against a wall of the bathroom. In the bathroom we have a sink, tub with shower, toilet, and a front-loading washing machine which is energy efficient and we wash usually with cold water anyways. We found that we preferred to set the water temperature to 109 degrees F. It can be turned up to 140 degrees. It takes the same amount of time that our gas hot water tank had taken to warm up. But it stays even once it comes to the temperature it is set at. More even and does not run out and plenty hot enough at our setting. We forget we have it. It will pay for itself within a couple years and we save on water heating from 24/7 to only as needed or wanted. Love it!

Electrical current requirements are very high, this is a 13.8kw heater (requires a double 60 amp breaker). Think this through to insure you have the electrical capacity to supply the unit. Would highly recommend this product.

I purchased the 13kw unit to try out a low budget hydronic in floor heating system. I didn't have much room to work with so this unit worked perfectly. I'm only running just shy of 3gpm through it at 110 degrees f with an inlet to outlet difference of less than 20 degrees f so this thing is perfect. Happy with it so far, hopefully it holds up the way I'm using it.

Amazing little heater, we are using this in our cottage, takes about 30 seconds to get hot water a little longer if the lake water is really cold. Uses 40 amps of power at 125 degrees Fahrenheit