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(More customer reviews)I had this model (Noritz NRC111-DV / 842) professionally installed about a year ago. My review will not focus on installation, but strictly on the unit's operation and performance relative to a conventional 40-50 gallon natural gas tank water heater which it replaced.
I'll start with some background on how I made the decision to go with this unit. I had a 15 year old 40 gallon natural gas tank water heater in my home that was showing signs of failing...excessive rumbling from scale buildup inside the tank and inability to to produce enough hot water to meet peak demand for my family of 5. I plan to stay in my home for the foreseeable future and had no problem making a long-term investment. The primary deciding factors for me were cost (initial cost, operating costs, maintenance costs) and hot water capacity to meet peak demand. I had researched several types of tank and tankless water heaters, including the traditional 40 and 50 gallon tank units, condensing tank units, solar, and tankless units from Rinnai, Takagi, Noritz, Navien, Rheem/Paloma, etc. I spoke with several trusted local plumbers and read professional plumber discussion forums about real-world problems encountered with the new tankless water heaters. All units researched were natural gas varieties, not electric or LP gas and most of my research was gathered in late 2009.
It's sometimes hard to sort through all the manufacturer's claims and marketing materials about why their unit is best, so I placed more emphasis on the opinions of professional plumbers for the quality/durability part of my decision and my own calculations (made some pretty complex spreadsheets) for the financial side of things. This process led me to conclude that Noritz was one of the better brands of tankless water heaters for the optimal combination of engineering/performance, manufacturing quality, warranty/durability, and cost.
Once settled on Noritz, I had to determine whether a condensing (unit being reviewed here) or non-condensing unit would be best and how both of those compared to a traditional tank water heater. From a hot water capacity standpoint, the 40 gallon tank could not cut it, and frankly, neither could the 50 gallon tanks unless I went to a "quick recovery" model which essentially just had a higher output burner and would cost me 50% more than a regular one. I could alter the showering habits of my family, which could be done currently, though in planning for the future, realized that there were many scenarios where I would still need more hot water (frequent guests/visitors staying with us, kids in sports, use of a whirlpool bathtub in master bedroom, etc.) than what I could get out of a 50 gallon tank. Condensing tank water heaters intrigued me, though ultimately proved cost prohibitive and were not nearly as efficient (overall energy factor, not just thermal efficiency rating) as I thought they would be. The "endless hot water" of the tankless units would certainly meet the peak capacity need (but be careful to "size" the unit to your needs appropriately), though also concerned me that people would start taking 30 minute showers routinely and cancel out the potential cost savings! In the end, the difference in cost for the condensing (more efficient, unit being reviewed) vs. non-condensing unit was about $600 in my case, and the extra capacity and efficiency made more long-term sense.
I do have to say that the current 30% federal tax credit played heavily into my decision to go with a tankless water heater, and I probably would not have gone this route without this "discount". In my opinion, the economics of tankless water heaters don't make much sense at current pricing levels (year 2009-2010) without a credit or discount, since the payback period vs. a traditional tank would exceed the typical 20 year expected service life of the unit. These units are also more difficult for the do-it-yourselfer to install and I believe many of the tankless manufacturers will not honor the warranty unless installed by a properly certified plumber. I say all this because the installation costs, especially if this is a retrofit into an existing home and not new construction, can add another $1-2K to the total initial cost. I found a quality local plumber certified by Noritz who offered a good price, which along with the 30% tax credit, made the installation costs basically free and I was just paying about what the unit itself would cost. If your total out-of-pocket cost is going to be more than a few hundred dollars above the cost of unit (net after tax credits, etc.), you should think twice. You can still do it, though your primary motivation at that point would be more about the environment and being green rather than pure financial sense and keeping more green in your pocket. Of course, some heavy users may find the endless supply of a tankless necessary and still more economical than putting together two 50 gallon tanks in series even with high installation costs and no tax credits.
So, how does it work? Quite well. You don't need to change anything about how you use your hot water fixtures...just turn them on, i.e. a shower, and wait for the hot water to start flowing. Compared to the tank water heater I had previously, I would say that it takes an extra 10-15 seconds to get hot water. This is due to the flow sensor taking a second or two to turn on the burner, a few seconds to actually heat the first amount of water that is now flowing, and in my case, an extra 10 feet or so of water pipe that was needed to install the tankless unit. The unit does all the work to heat water to your desired temperature and flow rate, and maintains temperature and flow well--no issues and the "coldwater sandwich" effect is pretty minimal with this unit. During the coldest part of winter, my incoming water temperature was about 40 degrees F and I set the output temperature at 115. This 75 degree rise gives me about 5 gal/min capacity, or about 300 gallons an hour. During the summer months, my incoming water temperature was about 75 degrees, and the 40 degree rise gave me about 9 gal/min capacity, or about 540 gallons an hour. Both figures easily exceed the "first hour" ratings of 40-50 gallon tank water heaters. In the worst case winter scenario, I have been able to have 2 showers running and a faucet moderately open (normal use) at the same time. If I attempted the same scenario with my old 40 gallon tank, I would run out of hot water in about 7 minutes. This really is a benefit of the tankless unit in that I can have 2 showers going at the same time, and have people take back-to-back showers without having to give the old tank water heater time to recover or limiting people to extremely short shower times.
I had to set my old tank water heater at about 130 degrees F in order to make the hot water last long enough. In contrast, I just set the temperature I want with the tankless (115 works best for me). There is a blower fan in the tankless unit that makes very little noise in my opinion (I expected worse), and since mine is installed in my basement, I never hear it running.
Since my furnace shares a gas line with the water heater, I could not verify the efficiency improvements until spring when I was no longer using the natural gas furnace. I am billed in MCF units (not therms) on my gas bill, and after I adjusted for year over year changes in outdoor temperature and its impact on incoming water temperature, used 48% less natural gas May-September than the year ago period when I was using the old tank water heater. My calculations were projecting about a 42% decrease based on the same hot water usage, so while my family's hot water usage remained much the same as the year ago period and we did not deliberately change our usage patterns, I suspect we used a bit less this past year and that accounted for the 6% difference in projected vs. actual. Further analysis revealed that about 2/3 of the 48% decrease (32%) came from simply having the burner off when not in use (an inherent benefit of all tankless designs), with the other 1/3 of the decrease (16%) coming from improved thermal efficiency when the unit actually was running. Here is an interesting fact: my unit runs about 35 minutes a day on average, meaning that nearly 23 and a half hours a day are spent doing nothing--no pilot light and no periodic burners to keep the water in the tank warm--nice!
The tankless unit requires a standard electrical outlet and it consumes 7 watts per hour in standby mode according to my kill-o-watt usage meter. When in use, the blower fan modulates and typically consumes electricity at a rate of 40-100 watts per hour. The only thing that takes a bit more electricity is the frost prevention cycle, which comes on as needed to keep the internals from freezing during temperatures well below freezing. This uses about 200 watts per hour and usually stays on for about 30 minutes at a time when needed, which isn't all that often. In any case, I calculated that this unit adds only about $1/month or $12/year to my electric bill at a rate of just over 10 cents per kwh--pretty minimal.
Maintenance-wise, it is important to do an annual flushing of the heat exchanger with some vinegar or similar solution to remove any scale buildup that might reduce the lifespan and/or performance of the unit. Make sure you have isolation valves installed with the unit, and then you will need a small portable electric pump, a 5 gallon bucket, 4-5 gallons of vinegar, and let it run/circulate for about 45 minutes. This is especially important to do if you have "hard water" as defined in the owner's manual. My water company reports 120ppm hardness or about 7.5 grains/gallon and this would be classified as "hard water" though not excessive. So, this costs about $10/year in...Read more›
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Noritz 0843 Series Direct Vent Condensing Water HeaterNoritz is proud to introduce our most efficient tankless heaters, the next generation in tankless technology - condensing heaters.This innovation utilizes a dual heat exchanger, a fusion of stainless steel and copper heat exchangers.The 100% stainless steel component captures the residual heat from the exhaust temperature to preheat the incoming water before it runs through the main copper heat exchanger.This results in dramatic reduction of carbon dioxide and increases the heater's efficiency level to over 93%!Another benefit of this technology is lower exhaust temperatures, which means less costly PVC can be used for its venting. A PVC adapter is built into the heater for easy installation.It's the coolest and greenest tankless water heater available today!This is the highest performing condensing unit on the market today.Some other brand(s) may have a bit higher efficiency rating, but there is a fine balance between the efficiency level and flow rate performance.At Noritz we strive to maximize efficiency levels without sacrifing the hot water output, temperature fluctuations, and water pressure.Comfort and safety is something we do not compromise on.Liquid propane, direct vent - indoor only (image is of the indoor/outdoor model)Condensing technology - The most advanced Noritz unit, over 93% efficiency level!
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