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Ok I got the house need hotwater help.

JoeG Member Posts: 88
OK I am used to a Indirect from a Boiler, But now I have forced hot air heat. the house has a 90 Gal whirlool tub, 2 showers washer,dishwasher. There could be four to six people staying in the home. I take long showers and hate to run out of hot water. My friend has a 50 Gal water heater Propane which runs out to quick.

I am looking at a 75 Gal Bradford smith Propane.

Or a point of use navien. What do you guys think. Thanks


  • Charlie from wmass
    Charlie from wmass Member Posts: 4,322
    Some times it is less costly to go with 2

    smaller tanks in series than one large tank. Also if piped correctly you can have minimal hot water when the one of the tanks fails. As far as the Navien goes where do you live and hows the water chemistry? How often will you be filling the tub? you could have a dedicated water heater for the tub and a smaller one for the rest of the home.
    Cost is what you spend , value is what you get.

    cell # 413-841-6726
  • TonyS
    TonyS Member Posts: 849

    Just installed another one today. I have been extremely pleased with the unit I installed in my own home 2 years ago and have 6 more installed to date. The standby loss on the 75 gallon is very high and the Navien is zero. The Navien is 98% efficient, the Bradford about 70 if your lucky. The Navien has a 15 year warranty on the exchanger, The Bradford 6 or 8. Purchase the right size unit for your demand, properly install the balanced flue and most importantly...size the gas line properly!! You will be very pleased you chose the Navien!
  • JoeG
    JoeG Member Posts: 88
    I love hot water

    Filling the tub maybe once a week, laundry prob daily dishwasher daily prob six showeres a day. What size naiven should I go with if I go that route? I got a price of $1,500 for there largest unit. How do you properly size the propane line? and I am unsure of the water chemistry I just got the place. I had hardwater at the house I owned  1 mile up up road.
  • TonyS
    TonyS Member Posts: 849
    Navien Installation

    How many showers are used simultaneously? It doesnt matter how many showers you take, with a tankless you can shower until your propane runs out. What matters is the GPM you use and what your incoming water temp is during the coldest part of the year. Then use the Navien web site to size the unit. Have your water tested and if your over 10 grains of hardness you may want a softner, if not I would be sure to use the tankless valve kit available from Navien to allow an exchanger cleaning every year. (easy to do and keeps your efficiency at peak). The old well has nothing to do with your new well, wells can vary 50 feet apart. Gas piping is figured by knowing the distance from your regulator, pipe size and making sure your regulator can handle total btu of all devices tied to it. I am assuming you are a homeower because you are unaware of how to size gas pipe. If that is the case, please hire a professional!!! Tankless units are getting a bad rap because 95% are installed improperly. You will be able to take 30% of the installed price for the tax credit so there is absolutely no reason to attempt this yourself
  • Larry Weingarten
    Larry Weingarten Member Posts: 3,331
    water demand

    Hello Joe:  You could have a pretty high hot water demand with what you describe.  You might want to look into the condensing heaters by AO Smith (Vertex) or Bradford White (ef Series).  The tank can help to manage your possible high demand and gas line sizing becomes less of an issue.  These heaters are relatively simple beasts.

    Yours,  Larry
  • CMadatMe
    CMadatMe Member Posts: 3,086

    gpm needed x temp rise x 500 = btus needed. Temp rise is the difference between the temp of hot water you want and the incoming water temp from the street or well.

    If want to make 8gpm of 115 degree water in my area. I use 8 because that will give me enough water for 3 showers and a kitchen sink all running at the same time.With a little cushion in case my wife decides she wants to run the dishwasher or a load of laundry in hot water. You can cut down your gpm requirements by installing water saving shower heads.

    8 x 65 x 500 = 260,000 btus

    I need a on demand tankless heaters that will product 260,000 btu's. 

    There was an error rendering this rich post.

  • bob eck
    bob eck Member Posts: 930
    hot water

    noritz tankless gas water heaters need to see if you will need a larger size gas line some models use 199,900 btu input or look at A O SMITH VERTEX 50 gallon tank type water heater that delivers 127 gph first hour and 92 gph @ 90*F temp rise only 76,000 btu input or vertex unit that delivers 164 gph first hour and 129 gph @ 90*F temp rise only 100,000 btu input. tankless gas you should have soft water or install a 3M aquapure cuno ap430 filter this ap430 can flow at 10gpm (cartridge needs to be replaces every 3 to 6 months depending on how much how tater you use) that keeps the unit from building up with lime and install isolation valves so the unit can be flushed out once a year by a professional contractor.
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