Customer Reviews for Rheem Performance 13 kW Self-Modulating 2.54 GPM Tankless Electric Water Heater

Happy with the cost, same as a conventional. Wish the unit came with other parts like an insulated bushing assembly for the 3 heavy duty wires that go INTO the water heater for its power installation. Bad mojo to leave the wires up against the edges of the metal like that. The reason why I give 3 stars is because of that, because I had to make a couple trips back and forth to retrieve THOSE items.

Ran electric, 3 40-amp bi-pole breakers, 3pair 8awg and 1 8awg ground. Line drops to 1/2" copper 12' in home, went to 3/4" 10' before tankless and drop back to 1/2" 10' after. I have had no issue with brass fitting and pex push-in. There is slightly longer lag time than from previous gas tank but it's seconds and nothing that concerns me. I will be adding an 8kw Rheem point of use, when I upgrade my 1/2 bath to full bath after saving space from water heater :)

While I’ve had two other on demand hot water heaters in the last 30 years this is my first Rheem. It’s by far the easiest to install and adjust.

I had read a number of reviews where there was an issue with leaking connections. This came with two options, compression fitting or threaded. I opted for threaded as I needed to adapt to 1/2" PEX. The set of fittings each had a chamfer to accept the compression ring (aka "olive"). So I cut about an inch of copper tubing for the olive to remain in perfect position once assembled. Coated it with sealing paste lightly. And for the threads I used thread past along with Teflon tape. (Yes, overkill. But there were a lot of complaints so I did the belts and suspenders approach.) And that was four months ago and the unit is performing flawlessly! Zero leaks.

It does not heat the water. Will not stay hot. Goes cold when showering.Blew cable off twice sending water all over the house!!!!!?I have had for two years and has not worked properly from beginning. Do not waste you time and money on this piece of crap!!!!!!!

I upgraded from a gas tank water heater to this tankless and I love it! The installation was a project in itself because my electric panel was full so I had to install a sub panel. It works great at the flows recommend. I order flow destructors for my shower heads to keep it at 2GPM.

Was working but 5 months in my kitchen sink is 100 degrees, bath rink 122 degrees, shower 98 degrees. IDKY. Can anyone help?

Easy to install, great product and work for a house with 3 bathroom i don't have any complaints

It was very easy to ensamble

excellent product, very nice

I’m a builder. I’ve had to replace 17 of these in the past 3 years. Almost burned one of the builds down. They break constantly. They are dangerous. Go with a different brand. These should be pulled from the shelf.

So far, so good. I recently purchased the 11kw model to replace a 20 gallon tank electric water heater that serves (an added on) bathroom with a stand-up shower only. It is now installed under the sink. I was already used to conserving my hot water in this particular shower so I already use a 1.2 gpm low flow showerhead with shutoff/flow lever (available at HD). I'm keeping the low flow set up since I think it'll help ensure that this tankless water heater is able to heat my incoming water and operate most efficiently. My incoming water is from a backyard well (SW Oregon) and it is pretty cold, so far this water heater delivers very adequate hot water and flow for me with the unit set at 115 degrees. Unless you're very knowledgeable, definitely hire an electrician for the wiring upgrades. My meter/service panel happens to be just on the outside of this bathroom wall, so the new wiring run was fairly easy. Don't skimp, get new high amp wiring and new high amp breakers installed as recommended by the manufacturer and you should be fine. The only thing I would consider before buying and converting to tankless is...how much hot water do you need?...and how many fixtures are served? Study what is available carefully and consult a plumbing/electrical contractor before tearing anything out first. I'm happy with the product and my results here.

We live in a 2700 Square feet home in Florida with 4 bedrooms & 3.5 baths. We have your typical dishwasher and washing machine. We purchased the 27KW unit for our entire house. The installation was easy and instructions straight forward. The unit is able to heat the water through the entire house, even while 2 are showering and the dishwasher is running. Overall, we are very satisfied with this unit.

So I studied over this tankless idea for a few weeks and here is some of my research/thoughts. 1. Test your inlet water temperature. 2. Take a 5 gallon bucket to each fixture and gauge how many GPM each fixture puts out in a minute. 3. Look at your electrical panel. This 27KW requires 3/40a double pole breakers and 3/8-2 runs of Romex. Minimum requirement is a 200amp main breaker. 4. If you have some electrical knowledge you can very easily hook this up electrically and easily shark bite/Pex the plumbing. 5. I can run 2 showers wide open hot @3.5gpm with 56.5* inlet temp and still have 1/3 of the final element left for more. 6. I just finished installing a water recirculation pump at heater and bridge valves under master bath sink and kitchen sink. I installed the pump on a smart switch which I have automated in our house. I have the pump on slowest setting. I plugged pump into a smart plug at tank. I have a smart outlet that plugs in at kitchen sink. You can turn that switch on at kitchen sink and it activates the tank smart plug to kick the water pump on. The bridge valves allow cold water in hot water lines to flow into cold water lines until the bridge closes internally (Meaning water is hot at bridge). Also have smart activation in master bathroom. No more wasting water waiting on it to heat up. When water pump is activated in any automation it’s set to turn off after 2 minutes per Smart Things App. BOKYWOX Hot Water Circulation Pump 3/4'',3-Speed Circulating Pump (RS15-6SB) This is the stainless model. Grundfos 595926 Bridge valves So now I have endless hot water and now instant endless. At .3gpm the flow meter activated first element. Hope this helps someone.

Installed this heater 3 months ago but wanted to evaluate performance etc before reviewing. Being a retired plumber I did install myself including adding breakers to panel and pulling wires. This unit requires 200 amp service and 3 40amp 2 pole breakers. Make sure your panel meets requirements and has available slots in panel. I left the original water heater breaker in but turned it off and disconnected wires. If you have a very good working knowledge of plumbing and electric you can do this install. Allow 1 day to do/run electrical work and 1 day to install heater. There will be some piping that will need to be reworked in order to make good clean connections to heater. Living in AZ we don't generally have extremely cold weather. Right now water temp into the heater is about 50 degrees and the Retex27 heats it to 110 degrees with no problem which is the temp I have set it for. 110 degree water is barely tolerable and not get scalded. Make sure to install a service valve kit as tankless heaters require cleaning of the heating elements. Cleaning elements is a simple process, just takes some time. I've seen some reviews say their lights dim when it turns on. I have not had that issue. Having a teen daughter it is nice not having to wait for a tank heater to recharge and she likes being able to stand under the hot water longer! Another myth with tankless heaters is it is instant hot water. Not true, it is endless hot water. You still have to wait for the cold water in the pipes to flow through and the hot water to arrive just like a tank heater. Another bit of info, the ECO27 is the same as the Retex27. The ECO27 has a lifetime warranty and Retex27 is 5 years. I did not have the luxury of waiting 2 weeks for the ECO27 to arrive as my old heater was leaking. If my research is correct Ecosmart manufactures tankless heaters for Rheem and parts are universal. Bottom line, I reccomend either of these heaters and tankless is the way to go.

I love this small tankless water heater. I had some leaks at the threaded connections but resolved that with Rector T plus 2. The reason I haven’t given this product a 5 is the temperature control is acting flaky. Turning the dial doesn’t change the temp. I wiggle the knob and it will change a few degrees then stop again. I called Rheem for a warranty claim. They were excellent, and are sending a replacement main board. The only problem I have with the design is that you have to dismount the unit to remove screws to take off the front cover. That could be easily fixed. I finally got the temp up to 105 degree setting and took a shower. The hot water was great! BTW I installed this in our RV on a 50 amp feed.

Just finished installation. Unless you are very comfortable with plumbing mods and electrical installation, factor in a professional electrician and/or plumber to the cost of this unit. This unit (18Kw) requires two separate double 40 amp breakers since the unit draws 75 amps. My old tank water heater had one double breaker and I had no available slots in the breaker box, so I disconnected a hot tub that wasn't used much (I'll go back and add a box for that later). The most difficult part was that the manufacturer required 8 gauge wire for both circuits and my old unit used 10 gauge. I had 6 gauge laying around so I used that but I would have been better off going to HD and buying 8 gauge since the 6 was a bear to work with and requires huge conduit (see pic) - the wire I used also had an outer insulation with added to the size. Do yourself a favor and research "wire ampacity" so you can correctly calculate the wire gauge based on the distance from the breakers to the water heater. Distance makes a big difference in choosing the correct wire gauge. Since my circuit was only 20', I probably could have used smaller wire. This heater is working well so far (2 days) and heats as fast as my old tank, but I live on hot Florida where the water comes out of the tap at 78 degrees.

The unit (Rheem RETEX 13) itself is excellent! My installation took 7-8 hours longer than it should have because 2 separate Home Depots' "experts" sold me the wrong parts. They both tried real hard but they made it harder than it really is. With the right parts a DIY install should only take 3-4 hours and it isn't hard at all. Parts you'll need: a 60 Amp double pole breaker, 6/2 wire, (plus I recommend a cut off box), PVC conduit, a water purifier (makes your unit last longer), 2 pieces of 1/2" female thread to sharkbite flex hose (the ones you use for a sink) with shut off valves (for servicing your unit), 1/2" CPVC, a 1/2"elbow, 2 pieces adapter 3/4" male thread to 1/2" CPVC (for purifier), and whatever adapters you need to tie into your water in and out pipes. Tools you'll need; a flat head screwdriver (for connecting the wires), a small phillips head (for the unit's cover), level (make sure the input hose is level), wire cutters, PVC cleaner and glue (HD sells a kit with both), 2 pairs of pliers or open ended wrenches (to connect the flex hoses to the unit and the adapters to the purifier), a screw gun (to mount the unit and the cut off box), some pipe clamps (I recommend clamping your pipes to the wall, a handfull of screws, plumbers tape, and plumbers paste. Before you decide to buy one of these make sure your panel has enough power coming in to accommodate the unit. Install; (Turn off water main and main breaker before starting) I started by running my wire from the panel area to my garage where it was to be installed. Next I took the 2 small screws that hold the cover on, then used the included template and mounted the unit to the wall. I put a screw part way in above the top of the unit so it would not slide up and off the screws while I worked on it. Next I chose a spot for my cut off box and mounted it to the wall. (Do NOT install this below the unit.) Next I installed a 12" long 1/2 female flex hose with built in valve and sharkbite end to the water in and out on the unit. On the hot side (left) I connected a piece of 1/2" CPVC with a 1/2 to 3/4 adapter on it, then glued that piece to the 3/4 hot pipe that runs to my 2 showers, garden tub, 2 bathroom sinks, kitchen sink, washing machine, and utility sink. On the cold side I connected the already installed flex hose to a piece of 1/2" CPVC. On the purifier I had already installed a male threaded 3/4" to 1/2" converter on the in and out so I glued the 1/2" pipe to the output. From the purifier input I ran another piece of 1/2" CPVC to a 90 degree elbow, then another piece of 1/2" CPVC down to a 1/2" to 3/4" converter attached to my cold water in pipe. After allowing 3 hours (yeah overkill) for the glue to dry I turned the water main back on and water tested the unit until I was satisfied there were no leaks. Next I ran a piece of the 6/2 wire from the cut off box to the unit, then connected the wire from the panel to the cut off box. Back inside the house at the panel I removed the 30 Amp breaker from my old water heater. I connected the new wire to my 60 Amp breaker and installed it into the panel. Before turning the power back on I turned on the hot water on a nearby sink and let it run for a few minutes. It is VERY IMPORTANT to get the air out of the line. With the water still running I threw the main breaker, then the water heater breaker. No sparks, no smoke, everything looked OK. Then I went back to the garage, held in the button to turn on the unit, set it at 130 degrees, and went back inside. It took (and takes) about 1 minute for the heated water to reach the sink but once it does it goes from warm to hot very quickly. With everything up and running I re-installed the unit's cover. I have been using this for 2 weeks now with no issues. After failing to install with the parts that HD originally sold me I did call Rheem's customer service to verify the install I had in my mind would work. They were very helpful! The quotes I got to have a professional plumber and electrician do my install were insane. I'm all for paying a fair wage but paying someone's mortgage and car payment for 1-2 hours work just didn't fit the program. This is NOT a hard job, I would give it a 4 out of 10 difficulty. *I used a few more pieces that what I described because I had to keep piecing it together with the wrong parts

This is a great concept, a decent price, and is good when it works but unfortunately the quality seems to be of the lowest standard possible. My first unit had two elements and one element fizzed out after 2 years of use. They replaced it at Home Depot (both home depot and Rheem customer service were helpful) but the second unit lasted 6 months before it popped and smoked when it was heating a shower. (It's a guest house so very frustrating that my guests have no hot water for their stay.) Upon removing it (easy to do except for the melted wires) I found the burn was extensive and could have causes a fire. Very dangerous. I hope they replace the unit but what they can't replace is my install time, my removing the unit and chasing down the receipt, warranty, and returning it to the store. Rheem needs to get their quality control back on point if they want to keep their brand on point.

We have a two bedroom and one bath house and this hot water heater has no problem heating water for us. This was a very simple installation and it worked right away.

This tankless water heater is small in size but really heats up our shower in a jiffy! No more waiting for hot water or worse yet, losing hot water during a shower. We love it.

Ran new 6/2 wire from the electrical box. New 60amp breaker. Flipped on the power and the LED says "OFF" "80 F". Pushing the dial doesn't turn it on. Rotating the dial doesn't turn it on. It is a dud. I am sorely disappointed and I can't return it because I am past the 90 day window. Buyer beware!

The product is easy to install but you do need 4 40 amp greasers and space for them in your panel. As long as you have the needed power the system works ok. I loved being able to get rid of my 50galon tank and have more storage space as my home is small. However two things I don’t like 1. The lights do flicker somewhat when hot water is being used which I can live with. 2. The hot water is not as constant as my tank system. I feel if I am in the shower and I have it at the right temperature if anyone uses hot water I have to readjust to get my hot water back. It’s a little odd getting used to it but if you are ok with that then you have endless hot water. I am currently building a new house and was going to go with a tankless system but now that I have experienced it my wife and I are rethinking this, we currently have a 2,000 sqft 3 full bathroom house and have the 36 kw system. Anything smaller will not work for us. It can crank out 140 degrees quickly which makes having multiple showers going possible.

Very simple to install, I am not a plumber and had no issues placing this into service, used ‘peck pipe’ & ‘ shark bite fittings’ yes a little more pricey , but saves time and mistakes are easily corrected. Heats up to 140 , plenty of hot water for just the 2 of us, but when guest are here, no one runs out. Super space saver..

This unit was quite easy to install. I'd recommend the compression fittings as the FPT adapters require additional adapters and teflon tape and/or pipe dope, so it was easier to make adapters from copper pipe and have them be leak free. One thing worthy of note is that their tables showing faucet usage are off from what most kitchen or bathroom faucets will use. 1.5 GPM is really a small amount of water, and if you run at a higher rate, you won't get the temperature increase you expect. This led me to believe the unit was faulty, until I measured the GPM. Once adjusted to the 1-1.5GPM rate, the unit functions as expected. Nice to have an "endless" supply of hot water!

We absolutely love the upgrade and added value to our home. However, I would recommend that you purchase the water heater yourself and find your own plumber and electrician rather than going through the "referral process" from Home Depot. The quote for plumbing the unit was nearly $1000, plus another $900 for the water heater and delivery charge (contrary to the store signage claiming free delivery with the purchase of a water heater). We would also have to contract our own electrician. In addition, the plumber recommended we buy a different brand which was not sold by Home Depot nor installed by him. Obviously did not want the business. We ended up ordering the water heater online instead of going through the store (saving us the $350 delivery charge), hiring our own plumber and electrician and had it installed for less than the quoted price from the recommended referral. Perhaps Home Depot needs to vet their "referral" companies and employees...

The only reason I'm not giving it a perfect score is because we did not hook up all 4 connections therefore we're not getting the full affects of the unit. We plan on hooking up the other 2 soon. We bought it a few weeks ago. The instructions were not as detailed as I think they should have been. The instructions were not specific to the model we bought, but we general to cover all of the different models. I liked the easy programming.

Replaced the 50 gal hotwater heater monster after it began to leak after 14 yrs. I initially priced upgrading to a 75 gal tank but opted not to once I found out that the tank weighed 320 lbs and it would not actually fit in the space. I also previously had got an estimate to install a tankless gas water heater but found out it was extremely $$$$ because it requires plumbing, gas, electrical and venting. My final option was to look in to a whole house tankless electric water heater and install it myself. I researched several brands EcoSmart, Stiebel Eltron and Rheem. In general the instsllation process would be the same so the big difference was price and what size. In our area the homes typically have 200 Amp service frrom the street which limited the size to the 27kw because the 36kw requires 300 Amp service as wells as it could possibly trip the electrical circuit for the entire house. For example, lets say you are running the Air Conditioner and 2 showers and/or the dishwasher all at the same time. The install was not as simple as it appears. First running the 8 AWG wire across the mech room was a beast because this stuff is very heavy and requires strong hands to cut and manipulate. Copper piping requires some skill when soldering I mean it looks simple on the YouTube videos but in practice it’s quite challenging but I did get the hang of it eventually. One tip though is to solder as many pipes together first (I recommend working outdoors) and then put the final connections at the very end. Or instead of soldering you can use the sharkbite connectors which are easier but they are more $$. I have set the temp at 125F and have been running it for a week. However I have since learned that when filling the 80 gal Jacuzzi tub I am unable to run the hot water at full blast because the heater max out is at 5 gal/min but my tub faucet max out is at ~7 gal/min. To adapt I have had to turn the faucet half way so the water heater can stay hot (keep up) which just means it takes longer to fill up. Otherwise the hot water is great on all 4 showers, sinks and other appliances so it was well worth the effort.

My 50 gallon electric tank heater was not providing enough hot water for our 2300 sq ft home with two full baths. I was familiar with tankless systems as I've been stationed overseas where tankless heaters are common. I love the endless supply of hot water a tankless can supply. So, I decided to but the Rheem retex 36. It seemed like it should do the job. Installation was easy enough and took me a total of 4 hours. An hour to install new breakers and run the wires. Two hours to drain the old tank heater because it was clogged with sediment. Then an hour to hook up the new tankless heater. It works like it's supposed to for the most part. It just seems like it takes its time to reach full temp after calling for hot water. Once it reaches full temp though it will give you hot water indefinitely. Only time it has problems is filling the tub. I can't turn the hot water on all the way or the flow is too much and the water will only be warm. Also, if the dishwasher, washing machine, shower and a sink are running I'll only get warm water. In my region it's supposed to be capable of running four showers and three sinks at once. Oh well. Worst thing is that this tankless heater actually uses more electricity. My electric bill went up 60 bucks extra every month since I installed this. Not efficient at all. I'd return it to try a different model but once it's installed Home Depot won't take it back.

This thing is great I dont even need to use cold water to take a shower we have the temp just right...