I've had this installed for about a month now and I'd say it works better than the 50 gal. Gas tank style unit I took out, which by the way ran non stop. I think there would be far better Reviews on this product if people would take the time and do their own diligent research on the products that they are buying . I find it amazing how many people are quick to leave a bad review on a product when their ignorance was the primary reason for the product not performing as they had hoped. That being said time will tell whether or not this product will last as long as the old tank style heater I had before but as of right now I absolutely love it and I expect to be enjoying the energy savings reflected on my utility bill soon.

It is true this unit does draw a 150 amps at full capacity but being an electrician I took some real load test on it and found out that the 4 circuits actually are staged, so unless you have 4 people showering at all at the same time you will likely never see anywhere close to that current draw.

I'll check back in a year-and revaluate this review but for now 5 stars baby

After hours and hours and weeks and weeks of researching and reading reviews I chose the Eco 18. It was torture.. but I'm VERY happy with the Eco 18. I've had it for about a month and no complaints. But do your research.. You have to consider the inlet water temperature, your electrical box capabilites, the size of your home or potential for multiple appliances or faucets running at once as well as your faucet GPM (gallons per minute).
I have a 2br/1ba home in South Western NC.
I was concerned if I got the ECO 11 it would struggle in the winter or if there was more than 1 faucet or appliance running. However, the ECO 11 has the least amount of electrical requirements.. It just needs 1 breaker which is what I thought I only had room for 1 breaker.
I was originally going to get the ECO 24 but I didn't have enough room in my breaker box for THREE breakers and it was probably overkill for my home but really didn't want any issues with not enough hot water.
I didnt realize it but my existing water heater already took up 2 double spots in the breaker box so the ECO 18 was perfect.
You also need to be aware of your faucet GPM or Gallon Per Minute. I read somewhere that if your GPM is too high it will not heat consistently or maybe not at all so I changed my shower head to a 2GPM shower head as well.. that also might be overkill.
After all the research and debating the ECO 18 is perfect and fits perfectly on the wall in my small laundry room. I highly recommend!

I did extensive research before purchasing a tankless water heater. The common problem seems to be that people are reading the GPM a unit is capable for their area and are expecting a nice hot shower. The GPM listed is based on heating water to only 105 degrees which is nice and warm out the unit, but by the time it gets to the other end of the house, it is barely body temp, if that. We found it needs to output between 120 and 125 degrees to get a nice hot shower (using no cold water). This in turn ups the kW required to heat the water... So to be safe, I picked the biggest model available right now (36 kW) and are tickled to death over the performance. It is solid, steady source of hot water for both showers at the same time. Love it. -- Note: If you don't have four 40 amp breaker slots available, no problem! Still get this bad boy and start off with 2 or 3 circuits(whatever you have available) and it'll use what you give it (albeit you may have to limit use to just one item at a time)... allowing you time to wire up for more power later.

UPDATE (5/15/2016): It had performed flawless for about 4 months. Then, suddenly, one day it said "OFF" and nothing we did (even with tech support via phone/email) fixed the problem. So, we had 3 days of cold water in the home until a new controller card arrived. Installed it (pretty easy) and voila! we're back in business. Tech support was easy to reach and the part was delivered via 2-day service. However, since then, it has turned itself completely off (not even light up) for no apparent reason. No breakers tripped... but recycling the breakers restored service. It has been a month now since last time it did that. -- I am still very happy with the purchase and would recommend it for anyone thinking about trying it.

I purchased the ECOsmart ECO 18 tankless water heater in April from Amazon during one of their open box warehouse sales for a very cheap price. The unit arrived as a wreck (as I expected it would). After beating out the smashed in cover (from improper shipping packaging) I inspected the inner workings, and found several parts ajar, and the cold water inlet fitting missing. Amazon offered an additional discount to me, so I took it, and set out to fix the unit, and replace the missing part. The cold inlet fitting has a one of a kind unique fitting threads, and I quickly found out that it's irreplaceable. A call to Ecosmart tech support was personally and professionally handled. The tech told me that this part is not available. He then went into their spare parts junk drawer, found one used, and sent it to me for next to nothing. I couldn't be happier with Ecosmarts service! The unit sat for 4 months until I had time to install it myself. I wanted to be sure it worked before gutting out my perfectly good water heater, so this report is what I found by permanently wiring, but temporarily plumbing the unit so as to not disturb the existing water heater. First of all, I live in South Florida (Broward County). Our water is fairly warm as supplied (70 Deg. Inlet temperatures in summer). I can only report how the unit worked with reasonably warm inlet temperatures. I've lived in the past in places where the water is 50 Deg. Year round coming out of the tap (NE Ohio), so I know I'm living in ideal conditions for a tankless electric water heater set up. I can report the following: I measured my normal shower water temperature. I like a hot shower. Using a lab quality thermometer, I find a water temperature of 95 to 98 Degrees is pretty darn hot. Maybe not hot enough to thaw out a frozen Ohio Linesmen, or firefighter with ice frozen to your face, but plenty hot for normal humans. I have the ECosmart 18 because electrically, my house only has 150 amp service. Larger Ecosmart units would overload my supply service. As tested, a 5 GPM flow (That's enough for two old fashioned shower heads AND a sink running hot, the outlet hot water as measured was 115 degrees. This is with the unit set as high as it will go (140 Degrees). The unit will maintain a 45 degree water temp increase over inlet temperature. Testing at a flow rate of 2.5 Gallons per min.(enough for an old fashioned shower head and a sink), the unit maintained 135 deg. With the temp set at 140. My unit had no problem maintaining 115 deg. output if set at 120 deg. With a flow rate of 2.5 gallons a minute. In testing, I found a constant 5 degree error between what the unit says the set temperature is, and actual. Not bad considering it's not an aerospace product, and some small gauge error is possible. The hot water tank I'm replacing is a 65 gallon unit, and IT DOES flicker the house lights every time a heating element turns on. (Noticeably annoying). I am super happy to report that the Ecosmart 18 unit does not flicker my house lighting. If you look very carefully, a very, very slight, teeny, weeinee load can be seen in the interior lighting of the house when the Ecosmart unit turns on, but it's MUCH better than my existing standard tank type water heater. The ECO 18 turns on with very little water flow (a sink just turned on enough to wet a tooth brush will trigger it to heat the water) so flow sensing is perfect, and not a factor at all. My overall opinion is that yes, the unit is delicate, and is prone to damage in shipping. Once placed in service, it's rugged enough to last a long time, and it works better than advertised. If you are in very cold water climate, you will need the biggest unit, and adequate power supply. Ecosmart lists what the unit will actually do modestly. If you read up on the specifications for each of their units, and match your water need and water temperature and follow the installation instructions you will never be disappointed by purchasing an Ecosmart unit. These things are great! Do your homework before you buy, and match it properly, you won't be disappointed! Removing that old tank water heater and replacing it with the Ecosmart gave me a whole lot more room in my garage, as an added benefit too!

Great system, instruction were easy to understand. I have had installed for several months now and could not be happier, we have three kids and we have yet to get unit to cut more than 2 of its heating elements on to reach our selected temperature,( in fact we tested unit with all faucets turned to hot in both bathrooms sink and tubs plus kitchen sink and clothes washer and dishwasher running only cut 2 of the elements on which is amazing,) and once it is hot it is truly never ending hot water, my girls will sometimes take 30 minute showers with no issue, but before after a short while they would run out of hot water in the regular tank unit. It is not instant hot water on tap though,(like stated) but we timed it within 45 seconds all cold water that is in pipes flushes and then hot. So just remember, that with a tank unit or a tankless unit, there will always be water in lines that set til water is needed so until the pipe clears for new flow of water, there will be a short period of cold water.