Noritz NRC66DVNG Indoor Condensing Direct Tankless Hot Water Heater, 6.6 GPM - Natural Gas

I did a lot of research on tankless hot water heaters before deciding on the NRC661-DV-NG.At first, I didn't know much about brands and types, so I started looking at prices. The lower-cost heaters had generally good reviews, but I didn't really like the idea of expensive stainless-steel venting and hot exhaust. That's when I discovered higher-efficiency condensing heaters with simple PVC venting, just like our high-efficiency furnace. While the cost difference seems unreasonable at first, the lower venting costs, higher efficiency, and cool exhaust made the condensing heaters more appealing to me. I tried to find and absorb everything about condensing tankless heaters, from reviews to owner and installation manuals.My research led me to narrow my choices down to the Noritz NRC661-DV-NG, the Noritz NRC711-DV-NG, and the Rheem RTGH-84DVLN, and after determining exactly how much hot water we'd need for our home, the NRC661-DV-NG seemed to fit our needs perfectly, especially considering the smaller size and natural gas intake requirements.The next step was to find a spot for installation, which is where we were really lucky. I had a spot on our basement wall directly under and to the right the two main 3/4" copper hot and cold water pipes, which made the water supply requirements easy to tap. There's also 2" PVC waste line directly below it, a 20A GFCI outlet (plus another 20A washer/dryer outlet off the GFCI) run to a dedicated 20A breaker, and a 3/4" main gas line directly to the right of that spot that already supplies our dryer. Sometimes things just fall into place for me, luckily.I downloaded the 661's installation and operation manuals to become familiar with dimensions and requirements. This gave me the chance to buy the pipes and fittings.Installing the NRC661-DV-NG is not too difficult, as long as you take your time, familiarize yourself with all of the supply and exhaust requirements, and get a good deal of the preparation work out of the way before you install the heater itself. To start, I bought two extra vinyl mount-masters for the 3" vent pipes, which I mounted 3' apart from each other on the outside of the house, terminating in downward-pointing 3" PVC elbows 2' above the ground. Then I mounted the 661 directly to the wall with four Red Head WS-3830 3/8" x 3" concrete wedge anchors, leaving about 5/8" of threads exposed so I could use 3/8" nylon-insert locknuts and washers. The exhaust on the side of the house is directly above the exhaust pipe on the heater, and the intake rises up from the heater and goes to the left and out. I connected the PVC pipes to the 661 with American Valve 3" flexible PVC couplings. I wanted to be able to remove the 661 without cutting pipes in the event of a failure requiring replacement of the entire heater. With the PVC venting out of the way, I ran a new 1/2" gas line, shutoff, and drip leg from the 3/4" gas main to the 661, then I connected the hot and cold water pipes using a Webstone 44443WPR service valve kit, which fits the 661 perfectly. There's no interference with any of the four shutoffs, either from the wall or from the pipes on each side. I used 3/4" copper/brass unions for the hot and cold water pipes, and 1/2" and 3/4" PVC unions for the pressure relief and condensation. The condensation drips into a 1/2" to 1-1/2" PVC air-chamber drip fitting on a 1-1/2" PVC standpipe. The pressure relief drains into a wye fitting at the lower section of the same standpipe.Before I tested the 661, I closed both shutoffs to our existing hot water tank, then slowly turned the water back on and bled the fixtures in the house. I plugged in the 661, and it worked perfectly the first time. The default temperature is 120 degrees Fahrenheit, which is displayed on the red LED display. I ran the water for a few minutes to clean the solder flux out of the pipes, and we've been using the 661 for several days since then. I drained and removed the hot water tank, which we'll recycle this weekend.Other than the "cold water sandwich", which is common to almost all tankless hot water heaters, we have no complaints about the 661 at all. In fact, this is one of the most satisfying medium-to-large purchases I've ever made, at least so far. Since there's no tank between the cold and hot water, the hot water pressure is actually higher than it was with the tank. And during operation, the 661 emits only a muffled two-speed fan noise, plus the sound of the gas igniting. It can't be heard from anywhere else in the house.I'm very happy with it, and I'd recommend it to anyone.Pros:- highly efficient- vents with Schedule 40 PVC- endless hot water- quiet operation- consistent, digitally-regulated output temperature- thorough, logical, easy-to-comprehend instructions- inside-front-cover documentation- small footprint- solid, precision-engineered "feel"Cons:- cold-water sandwich (not Noritz's fault; this is common to almost all tankless heaters)I'll try to update this review as we gain some experience and time with this heater. From what we've seen so far, my research really paid off. The NRC661-DV-NG has exceeded all of my expectations.UPDATE, 21-Jun-2016: Nearly six months later, this water heater is still operating flawlessly, and, from what I can roughly calculate, our natural gas consumption is about 10-20% lower. It really is well worth the money, and now I'm thinking of adding the RC-7651M remote control. In another six months, I'll perform and report on the vinegar flush and rinse.

Works great but you may experience a delay in getting hot water to the faucet compared to old hot water tank.I have copper pipes so they are giant heat sinks that are no longer being kept warm by the old water heater. As a result they draw heat out of the water when it is first starting to run, which I expected having dealt with copper pipes and soldering. This should be less of an issue if you have PEX or PVC pipes. To help reduce the heat loss I have placed insulation on all the hot water pipes which has helped reduce the initial hot water time and holds the heat in during the morning so there is very little lag during heavy use periods.If I was on city water I might be concerned about the extra couple of gallons that must be run to get the initial hot water in the kitchen (furthest run).The bathrooms are near the water heater so they take about half the cold water before hot.Once the hot water is there it is never ending. No longer any concerns about family taking long showers or baths.Also this will be great for the initial hot tub fill I will be doing this week.Be sure to check your gas meter capacity. I went with this unit because of the 120K Btu. This plus my gas furnace, gas dryer, gas double range added up to a max Btu that my meter could handle. If I had been over the rating, which would have been the case with a larger unit needing 199K Btu, the utility would require a meter upgrade at a charge of $500

My home is 3 floors and 2400 square feet. We installed it in the basement level in a utility room. Family of 5 we have had no issues of not having enough water. Factory setting was perfect so we have not had to adjust it. We can have two showers (which is not common) at the same time and there is no break in the temperature. Wash machine or dishwasher combined with a shower at the same time also no issues. It gets nice and hot and continuous. The minor thing that we had to get used to is that if it had been off for a while it takes about a minute or two for the hot water to make its way into the pipes and for the system to pump it though to the 3rd floor. This is not inconvenient and was a slight behavior change. Some people put in extra circulation pumps etc... I have had no need. There are many brands out there but this one is perfect for my size home and a family of 5.

I like this water heater. It works and just keeps cranking out hot water, and is very efficient. However, it is really noisy. Every time someone turns on a hot water valve it comes on with a loud buzzing/whirring fan sound that I can hear inside the house. That's more annoying than I expected. It also takes longer to get hot water than with the old tank water heater. It was quite a bit of work to install, and it requires frequent descaling and a new cartridge every year or so. I never had to worry about that with the old tank water heater. I am looking forward to my gas bills being lower though. So, I'd buy it again.

Over all I'm very happy, the use of water with the unit is different than a water heater, such as rinsing dishes by hand, one doesn't turn the water on and off, but leave it run at medium open on faucet, or at least that is how it works for us. Showers, laundry etc. the same though. I hired a licensed plumber who had not installed one before, he did a great job, so said the city inspector. The inspector has had years of experience with this companies products and thought very highly of them.

This is a really nice unit. Saves me about 30 bucks a month over my old tank style electric model. And, if you have soft water(I have Cull....) you don't need the pain in the butt leaky fittings they tell you to buy with it. Just a little heads up. Other that that, it's a nice little unit that doesn't take up a lot of space like a tank style unit does. The plus side is that it will operate with a 1/2 inch natural gas supply line whereas most require a 3/4 inch line.

Great value and quality for the money, installed about 3 months now, love it just had to get used to the 'Cold Sandwich" affect, have to let it run a bit to get to the hot stuff, but small price to pay for unlimited continuous hot water :) Know that none of the connection hardware is included venting pipes etc.