yeshwant91, A bit off topic but related... I'm not familar with all the combi units your considering, but consider carefully if those units will meet your needs. Some of the combi boilers I'm aware of have significant limitations. For example, in their instant hot water production mode if you exceed their max flow spec they will allow the additional flow and just start lowering the temperature of the heated water. In reality this may mean certain units are only good for a single point of use at any given time. So you might not be able to take a shower and wash your clothes at the same time. A couple years ago I was considering a Rinnai whole house instant DHW heater. They are very powerful units and have flow limiters so requested hot water temperature is always achieved. If you ask for more hot water than it can produce they will just ignore the demand for additional flow. Not sure which (if any) combi units also incorporate this feature. I agree with dross - if you can swing a 220V line do it for the sake of a much wider choice of washing machines with proven track records. I believe Miele/Asko/Bosch all use 220V-15A circuits for their washers. I understand you won't need it for the dryer.

As I type this my 14 year old tanked water heater is being replaced with a Navien 240. My warranty is 15 years on heat exchanger, 5 years on parts and 1 year free labor. No requirement for an annual service. Additionally, the company installing the Navien has a policy that guarantees if, during the first year I have the Navien, I'm unhappy with it, they'll remove it, and fully refund my money. They said they've never had a customer claim that benefit. All of their customers are happy. Last year, when the state tax credit was in effect, they were installing 2-3 Navien units each week. Install rates have fallen off a bit since the state tax credit has been dropped. Interestingly, they're installing Naviens only in existing homes. They were also candid that, like other new technologies, there were some hiccups a few years ago that needed to be worked out. In their opinion, all problems have been resolved, and today the best, most reliable tankless units on the market are Navien and Eternal. I chose the Navien because the heat exchanger is stainless steel, not copper, eliminating the need for the periodic de-scaling required of other makes. And because it appears easy to operate...more so than the Eternal. I'm nervous at the change. And I'll post back here after I've lived with the Navien for a month. I've got house guests coming later this month, and it'll be interesting to see how it performs with lots of showers, laundry, dish drawer use, etc. I'm so pleased to hear that Rob is delighted with his new Navien.

Hi Lisadlu, I guess it went fine....The water went in and it came back out. I didn't really see too much dirty "stuff" in the vinegar bucket, or the rinse bucket at the end. I think there was a little red residue in the rinse water which I think was the from the HOT water hose (it was red). Due to the low amount of "Stuff," either I didn't need to do it, or I didn't do it right. I had read somewhere NOT to turn off the electric, but the instructions in my manual clearly said to turn it off, so I did. I was lucky to have the valves already installed by the original installers. It just made sense to shut off the cold in and hot out, and then attach the hoses and run the cycle of vinegar for an hour or so. I guess the plumbers charge so much because of the time, not the technicality. I wasn't too clear on the rinsing part. I let the cold water run in to the heater and out into a clean 5 gallon bucket, then emptied it and let the 5 gallon fill one more time. I think I was supposed to let that 5 gallon rinse run through a few times, but I didn't see the point. I just let the hot water faucets run for a while. There was a slight vinegar smell when I first turned them on. I did it all by myself! No hubby required. I watched a few videos and consulted my owner/installer manual. I made sure to do it on a Monday and not a Friday in case I @#%$'d it up! (figured emergency plumber on a weekend would cost $$$) Good Luck!

I installed a tankless 6 years ago and will never install a tank again. I did it myself and will do it again if I am ever in a new house. I have a 120k Noritz unit that performs flawlessly. I just don't get it guys. Installing a tankless without recirc is like trying to start your car with a half dead battery. Really! "Your builder is right, it defeats the purpose of tankless" nonsense! I did not have recirc initially. I learned by experience you do not just replace a tank with a tankless. It is a bad result for hot water supply. Slow and inconsistent. Internal recirculation tanks might help but never having used one I have no opinion. But unless you circulate water and insulate your pipes to maintain the heat you are really missing the boat. Recirculating inside the heater means your pipes are cold and it takes longer to get to a tap because unlike a tank there is no pressure in the lines to radiate towards the taps. Why store water inside your heater when you need the heat in the pipes for faster delivery? That is just a limited solution to the issue in my opinion. How much does it cost to keep the lines hot. Depends on heat loss and vol. of water in the lines. Insulate!!! I would say my pipes take very little in cost to keep hot. Maybe $5-7 a month. I used 3/4 inch pipe for recirculation to store more water for start up and to feed 110 degree water into the heater. I do not have a timer to shut off recirculation at night so I could save a few bucks if I did that. Its a simple thing to lay out. You go to the last tap in the system and put a return to the heater from there. You need to have a cold water supply for the recirculation. A one way check valve between the recirc and the street supply prevents hot water from pumping back to the street as hot water pressure rises. A second check valve goes between the last tap and where the street supply feeds the recirc line to prevent cold water pressure from the street from back flowing through the hot water lines. Why any builder would not just put a return line back to the heater is beyond me. Its really not a lot of extra work. Especially with all the cheap Pex being used now. A small grundfos 1/25th hp pump is all that is needed in most cases. I use a Honeywell aquastat to trigger the pump. The pump engages maybe once an hour for maybe a minute to raise the water temp from 105 to 110. Heat loss? Did you insulate the pipes you say are losing heat from? You can lnstall a timer to turn off recirc in the night so you use no energy at all. You can do the same during the day when you are not at home. For some families you could have a daily timer that changes recirc to match your schedule. The hot water works with the recirc off, it just does not work properly as iz well known. Tankless is a superior technology. I did not think the endless supply would matter to me, its noticeably better. A tank cools as soon as you start using water out of the tank and cold water replaces it. The temp drops and drops the longer it flows. A tankless heats water on demand and it is maintained at the same temp. Its really is an advantage. But, as has been stated here by users, un managed hot water supply sucks and who cares if it costs a little bit of money to heat and pressurize your pipes so hot water is instant. Its way less expense than keeping 40 gallons of water hot in a tank. I would never heed the advice by someone on this thread that you don't need recirc. Have your builder install a true full house recirculation system. Don't pay attention to this "you don't need it stuff." If the builder balks or talks down to the idea get someone who knows what they are doing to come install it and over ride their obstinate attitude. Just do not listen to the talk of having a better system is not needed. You are going to great expense to have the best hot water supply you can have. Don't let someone with out your best interests in mind wreck your enjoyment of a great tankless system. Recirc all the way!!! Gee people, why would anyone not do this in new construction when its way easier to do.