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267 of 277 people found the following review helpful
on June 12, 2013
Verified Purchase
The Rheem RTE “tankless” water heater is ingenious and the energy savings will pay for both the unit & install costs in only 17 months vs. keeping my 50 gallon electric tanked water heater.

I'm a mechanical engineer and was drawn to the unit's energy savings and ultra-compact size (9 x 10 x 5 inches {yes inches}). You likely won't believe it can provide you the hot water based upon it's small size. Booboo – you're wrong.

Why it works for me:

1. I'm a single person, take 1 shower a day, and do 2-3 loads of laundry a week, plus dishes.
2. I have a low-flow (1.5 GPM) [gallons per minute] water-saver shower head in my bathroom, saving water and also reducing the need to heat larger water flows required by standard shower heads generally at 2 - 2.5 GPM. However, even if you have a standard shower head – this unit will do you fine since it is rated up to 4 GPM.
3. A new tanked water heater (gas or electric) is $400 + $375 install costs. This unit is $193 + my $375 install costs to run a 60 AMP electric service and plumbing installation for the unit by an electrician/plumber.
4. It's tiny size (you won't believe it can work) frees up a storage space the size of the old heater.
5. Instead of having it on the highest heat setting, I set it to only 60% of the highest heat setting so that this setting provides me a very comfortable warm/hot shower water temperature without turning on the cold at all – therefore, heating only what I use (not blending overly hot with cold water) – further saving energy. I just set my clothes washing machine on “hot” and actually it is therefore at my hot/warm shower setting. Again, reducing electricity while working fine for clothes and dishes.

Financial Return on Investment:

1. Unit cost = $193 + $375 installation (electrical 60 AMP service & plumbing) = $568
2. Operating costs for a single-person based upon 10 cents / kwh (Nevada Power rate):

a. 7 showers / week @ 8 minutes each = 56 minutes 1 hour / week
b. 3 loads of laundry = 3 x 10 minutes hot water each = 30 minutes 0.5 hour / week
c. 7 sink loads of dishes / week = 7 x 5 minutes of hot water = 35 minutes 0.5 hours / week

Therefore total time the unit will be on / week = Total: 2 hours / week

b. The heater on full-blast is 13 kw (kilowatts) but I set it at 60% of this. Therefore 13 kw x 60% = 7.8 kw power usage / hour when the unit is turned on (based only upon actually using hot water).
c. Weekly energy usage is therefore:
I. 7.8 kw x 2 hours / week x 4 weeks / month = 62 kwh (kilowatt hours) / month
II. 62 kwh x 10 cents / kwh (Nevada Power Rate) = $6.20 / month
III. My old 50 gallon electric unit cost = $40 / month
IV. Savings $40 - $6.20 = $33.8 / month energy savings
V. $568 (total cost for unit and install) / $33.8 savings per month = 16.8 months pay back on investment.

Summary: based upon $193 heater cost + $375 install cost (depends on your contractor), the total cost of $568 is returned to you in monthly energy savings in only 16.8 months.


1. You are a single person or couple who don't use that much hot water in a month.
2. Household members do not need to take showers, wash clothes, and do dishes all at exactly the same moments of the day; since using 2 showers, a washing machine - all drawing hot water – will reduce the heat increase to each if all used at the same moment.
3. Compared to a normal tanked water heater – the total cost for unit & installation is similar
4. The unit has a 10 year warranty, however if it ever goes out – sooo easy to install a new one.
5. Don't believe the negative reviews – my electrical/plumbing contractor was “AMAZED” at it's performance in such a teeny tiny package.
6. You love the idea of saving money, energy, and water.

FINAL NOTE: Most important –

1. Most people do NOT have the electrical experience to “safely run a 60 AMP service” required for this unit.
2. Print out this product's info page and get three quotes from licensed professional contractors to confirm your installation costs prior to purchasing it.
3. Note: Older homes / mobile homes may not have electric service that can handle such a large 60 amp service. This is why you need a professional to provide you a free-of-charge home visit & quotation for electrical & plumbing service.
4. Get 3 FLAT-RATE quotes – no hourly quotes from licensed contractors or you'll get charged extras later.

Do the above, and you know exactly what “professional & safe” installation costs are prior to purchasing the unit.

SUMMARY – I'm amazed ! I love it ! Electric savings saves me $34 / month, pays for the total installation and unit in only 17 months, and frees up a huge storage space. Do your “installation costs” home work first.

What a hidden gem !
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99 of 101 people found the following review helpful
on April 6, 2012
Verified Purchase
Rheem RTE 13 Electric Tankless Water Heater, 4 GPM
I just finished installing this water heater in my yoga studio. I have a powder room and an outside shower, with a laundry sink in the garden shed. This heater is amazing. I have it set on "medium" and the water is plenty hot and almost instantaneous. I have used the shower a few times and not run out of hot water. Plenty of volume for my needs. It is about the size of a Webster's dictionary and very easy to mount. Be aware that you need to run at least 3' of copper tubing from both sides of this thing so if you have plastic pipe you will have to make modifications. Also, you need to have enough electric service to handle a 240v, 60A breaker. It says to use 6 ga. wire, but the pigtail on the unit is 8 ga. Use your own judgement here.
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111 of 117 people found the following review helpful
on July 14, 2013
Verified Purchase
I wanted to use this atleast a couple weeks before reviewing it. First off, I live alone, but in a 3 bathroom house. I have been keeping 50 gals of water hot in my basement for 25 yrs and finally decided to wake up. I installed this heater as a whole house heater in the basement where my old tank heater was. I was ready to deal with less than super hot showers, but I am amazed how well this works in both 1st floor bathrooms (1 tub, one shower), and even the 2nd floor bath(shower). Hotter water than I can tolerate in each one. BUT I DID LEARN THIS! I bought a 1.25 gpm shower head figuring I better cut back from my 2.5+ heads with this much smaller heater. WRONG! The first floor shower was hot and cold because i wasn't pulling enough hot water to keep the heater on. I then tried a 2.0 gpm in the downstairs shower. PERFECT. Consistent water as hot as I could want it (and I do not have the heater at full steam). Knowing the 2nd floor shower would have less pressure, I left the 2.5 gpm head on there, and again, perfect shower, no temp changing, hotter than I needed, and lasts forever if wanted. It still takes the same amount of time for hot water to get to my 2nd floor. I have always preferred a 5 min shower with a good shower head vs. a 10 min shower with a trickling shower head, so I do not think I am wasting any water. AGAIN, I am one person in this house, and have no problem NOT doing laundry, showering, and/or dishes at the same time. A couple or family could be perfectly fine with this heater if they could aviod doubling up on water usage. Not really that hard in my book, but your call. I also insulated ALL exposed pipes in my basement, under sinks, and some in the walls to help keep the heat in the pipes. Bottom line, so glad I did this, I think I will be saving tons of energy and $$$ not storing all of that hot water I am not using. I don't know why the manufacturers dont warn of using too low GPM shower heads, but if you think about it, a 1.25 gpm shower head is less than 1.25 gpm at 60 psi, and at 1/2 hot and 1/2 cold water, you are teatering at the heater on/off threashold. simple math.
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126 of 137 people found the following review helpful
on October 24, 2010
Verified Purchase
I expected a unit of this size to put out hotter water when flowing to a single sink. It's useable but not as good as others I've used. I'd hate to think of what the lower wattage models would do.

It also has the annoying habit of occasionally switching on for a few seconds even when not in use, there's no reason for this to keep the few ounces of water it keeps inside already warmed up.
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63 of 67 people found the following review helpful
on October 24, 2012
Verified Purchase
Make sure you understand the power requirements of this unit before purchasing it! I purchased this unit thinking the only thing I would need to do is remove the 15 year old 50gal hot water heater and install this tankless model. Boy was I wrong. It ran for about five minutes and then tripped the breaker. My breaker box wasn't properly labeled and I thought this was hooked up to a 40amp breaker. It tripped the 25amp breaker at 240V. So I spent a couple days and some trips between Lowes and Home Depot getting supplies to rework the plumbing and add a new receptacle for the electric rated at the specified 240V at 60amp with very difficult to work with 6/2 wire I had to run from the breaker box, up into the attic and down between the walls. I spent about $215 through Amazon on this unit in addition to about $250 more dollars in plumbing and electric supplies/tools. It would probably have cost $500+ for someone to run the new outlet and whatever the current rates are for the plumbing. In addition to installing this unit, my water valves began to leak (went bad from not being used. I broke whatever seal they had when I turned the water off). One negative I would like to mention though is that 6/2 wire barely fits into the connectors of this box although it comes with a short cable of its own. I ended up making a longer cable and had to cut pieces of the 6/2 wire off to reduce the girth so they would fit into the connectors. In addition to that, the connector holes are round (vs "U" shape) and the wire snags on the sides while trying to get them into the holes and clamp them down. You cannot purchase a standard plug and socket at Lowes or Home Depot. 60 amps is some serious power draw. You can get a plug and socket for $100-130 through Amazon. I decided that is way too much money and went a different route. I temporarily hooked this unit straight to the breaker box as most people will have to do. Later after getting some more advice from experienced electricians, I cut the wire to make a longer power cable and used wire connectors rated at 4 gauge (do not use wire twists! ! ! Most cannot support 60 amps).

***Installing this unit can be very dangerous and could result in death if you are not sure of what you are doing. I consider myself a do it yourself kind of guy and a quick learner. I had to seek professional advice before installing it. If you have any hesitation on installing this system, I recommend you have it professionally installed considering you are working with the lethal combination of electricity and water.

This unit runs great from my two car garage. I had some doubts given the reviews I had read and seeing the size of the unit. Home Depot actually has this unit on their site with 50+ strong. I recommend checking those out and Amazon's. Well, this tankless heater puts out scalding hot water on the Med-high setting. I live in FL, so the ground water temp is probably around a modest 70 degrees. So this 4.0 gal/min unit is more than enough for my 2200 sq/ft home with 3 bedroom and 2 bath. I'm not sure if I could recommend this to someone up north where ground water temps can get to freezing temps. So far I've had this unit installed for a little over one week. Water heats up instantaneously and I don't notice any performance difference compared to the 50 gal hot water heater it replaced other than the hot water on this thing does not run out as long as there is power to the house. Again, I would like to emphasize that the water is heated almost instantly in the box when someone turns on the hot water (little to no delay). I put my hand on the hot water line (copper pipe) when it was cold, had my wife turn on the hot water and the line instantly became warm/hot. This is my first time experiencing a tankless water heater and I'm almost a full believer. The only thing holding me back is to see what the new power bill will look like over the next couple of months. Other than replacing a 15yr old water heater on the verge of disaster, I installed this unit to conserve power and lower my power bill.

Power Bill (me rambling about cost savings goals which also = energy savings too):
I recently installed a Nest thermostat also purchased through Amazon three months ago for my A/C resulting in my power bill droping $35-40. I'm hoping to get at least $30-50 per month less on my power bill with this tankless hot water heater installed from what I've read online. I averaged $120 power bill. I'm down to around $90 with my Nest thermostat installed. Hopefully It'll be between $60-70 on my next power bill; or maybe that's just wishful thinking...

Directions Manual:
The manual is very basic and can be found on the Home Depot site. Specifications on the power requirements can be found on p19 and the pipe fitting requirements and cautions on p8.

So far I'm enjoying this unit. I may update my review later to mention cost savings/gains. If you have any questions, I'll do my best to get back with you. I deducted one star for fit and finish. There really is no wow factor or aesthetic appeal (packaging and product) to this device.

So I've had this unit for around three years now. I have experienced no degradation in performance and it has ran flawlessly. No regrets yet and I'm still averaging $20-30 less on my power bill. Now that I've had two children since then, it very convenient not worrying about running out of hot water with all the bathing, laundry and dishwashing going on.
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191 of 220 people found the following review helpful
on April 14, 2011
The first unit I installed started to leak after 2 days - the joint between the two heating chambers. Rheem sent a replacement. The second unit turned on spontaneously - when the faucet was closed and caused a massive build up of pressure and then fried the control board. Fortunately I caught the unit turning on and opened the faucet - it was like a giant espresso machine. I have no doubt it would have exploded had it not been caught in time. Rheem sent a second replacement. The third unit, same problem as the second. This time my wife heard noises from below the sink and ran to the breaker to turn it off, not before one of the elements inside burnt out. These units are dangerous. I spoke at length to Rheem customer service who weren't too bothered and said if I thought there was a problem, I should write to customer service. These units could kill somebody or serious burn - steam burns are the absolute worst! Stay clear
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24 of 24 people found the following review helpful
on September 18, 2014
Verified Purchase
I received a defective product from Rheem. I purchased the unit from and received it on June 25, 2014. I installed the plumbing but could not get a qualified professional electrician to install the electrical until Sept. 11th. He used #6 wiring and a double pole 260v breaker. When we turned the water heater on, it worked perfectly fine and delivered hot water as far away as 40 ft. The next morning when I turned it on I received no hot water. My electrician returned, checked everything out, including doing a diagnostic of the water heater we found on the Rheem web site, but he was unable to find the problem. I uninstalled the water heater and boxed it up, planning to send it to Rheem for warranty replacement since my Amazon return policy had expired.

I called Rheem customer service to make sure I followed proper warranty procedure. They referred me to the Technical Assistance unit. The first technician ask me if I was near the unit and I told him I had it in a box ready to send it back. He said he needed to run me through a diagnostic procedure and I told him a qualified electrician had already done it and declared it defective, probably in the small mother board of the unit. The technician told me I would need to reinstall it and call back to be guided through their diagnostics even though I told him we had done so using their recommended diagnostic procedure for the unit posted on their website. So, I reinstalled the unit and called him back. He asked me to do one check which I did and it did not test out. He stated he would need to elevate my problem and I assumed he was elevating me to customer service to return the water heater. Instead, I received a higher level technician who guided me through the same process my electrician had gone through via the Rheem web directions. The Rheem water heater checked out defective via his instructions.

He asked where I purchased the unit and I told him on, but my return policy had expired and since the unit was defective I was returning it to Rheem via their warranty. He took additional information and told me his supervisor would need to approve the return and replacement. Hence i assumed a replacement would be sent. About 2 hours later this technician called and told my that while my unit had been purchased through it had been sold via a third party distributor who was not supposed to be selling them on I told him that was Rheem's problem not mine; Rheem made the unit with a warranty and I was exercising my warranty. He gave me the distributors name and phone number and told me I would need to work through them. Lesson learned "Rheem does not back up its warranty without putting one through a hassle." But the review does not end here. I called the distributor. They asked for the order number, checked it and said they had only shipped the unit, but it had been purchased through a third party seller. Hence they were not responsible for replacing it.

Enough is enough. I called's customer service and explained my situation. The Amazon rep asked me to give her a couple of minutes. After about a 3-minute wait, she came on and said a replacement would be sent asap, but it may not be delivered for over 4 weeks because she had to place on back-order. I wasn't happy with it, but at least I was getting a replacement without the hassle Rheem put me through. She immediately emailed me a postage paid return mailing label to send the defective unit back to them. A few hours later I received another email stating they had found an alternate distributor and my replacement would arrive in two days. It arrived in less than two days and I installed it. The new Rheem RTE-13 unit works fine so far (2 days), but only time will tell. If it malfunctions, I assume I will have to start a replacement hassle with Rheem again. I most likely will not replace it with a Rheem due to their initial "poor customer service" even though I have two large Rheem units in my home that have performed well for over six years.

I give 5 stars for how they handled this situation and Rheem no stars for their customer service.
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24 of 25 people found the following review helpful
on December 2, 2013
Verified Purchase

I have had this same unit for 7 years now. I just had to replace the original unit. These aren't made by Rheem, They're made by Titan Tankless. I had a titan but replaced it with the Rheem unit because its on Amazon Prime and got here on a Saturday.

First thing to know, this is a SINGLE USE unit. Which means that you cannot use this and 3 other water outlets at once. Don't run the washing machine and expect to take a shower at the same time. It just doesn't work that way. If you want to do that, you need to buy a unit that costs 10 times as much as this one. Don't buy a $180 tankless heater and expect it to work as well as a thousand dollar unit.

Second.. MOST IMPORTANT THING. YOU NEED TO ADJUST THE VALVES ON EACH OF YOUR HOT WATER OUTLETS. ESPECIALLY THE TUB. If you do not have low flow water savers on your faucets.. ADD THEM RIGHT AWAY! Obviously you cannot buy one for your tub. So go under your sink and turn the hot water side valve to half between completely off and on. Then run the hot water until it comes out hot.. Is it too hot? If so then open it up more and let the faucet run for an extra few minutes to give the temperature time to adjust. Keep doing that on EACH one of your faucets, shower heads, tubs. Even go as far as adjusting the valve on your washing machine. Is it too cold? Try turning the knob up to on the water heater itself. I keep mine one notch above Medium and I have almost scolding hot water at each faucet. Keep adjusting your valves until you get it just right. MAKE SURE YOU LET THE WATER RUN FOR AN EXTRA FEW MINUTES AFTER EACH ADJUSTING. IT TAKES TIME FOR THE WATER TEMP TO GO DOWN AFTER BEING SO HOT.



This unit is awesome if setup properly. It can easily last you 5 to 6 years and it has cut $30.00 off my electric bill each month.
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51 of 59 people found the following review helpful
on April 9, 2012
Verified Purchase
We changed our water heater from a 50 gallon gas heater that was costing us over $400.00 a year just to heat water. We have a 3 bedroom 2 bath home and just my wife and i live there. I placed the Rheem heater on the end of the house where most of the water is used. I ran the wire to the breaker and tied in the plumbing. This was very easy as the water lines in the house are pex and the fittings that can purchased at Lowe's are basically press on. The entire install took all of about 4 hours and that includes two trips to Lowe's because I picked up one fitting that was the wrong size. The water heater is amazing. Provides all the hot water we need even while Running the shower, the dishwasher and the bathroom sink. Would recommend this to anyone who wants to save a little money.
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17 of 17 people found the following review helpful
on April 11, 2012
Verified Purchase
Love it! Hot water instantly. Using it in our bedroom, bathroom, Laundry room and is totally capable of keeping up with usage. Love the fact that I don't have to remember to turn off breaker when we leave lake house. Highly recommended.
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