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Best product for domestic hot water?

Brian S
Brian S Member Posts: 12
I have a customer (who is also a relative), looking to replace his 75 gallon gas hot water heater. Very large house with 4 full baths and forced air heat. Money appears to be no object. He is set on getting the top of the line and most efficient system. If this was your house and installation cost were irrelevant, which type of system and brand would you choose?


  • Jean-David Beyer
    Jean-David Beyer Member Posts: 2,666
    Not enough data.

    I am a homeowner, not a pro.

    Since cost is no object, I would use a mod-con with outdoor reset. I would heat the house with it as well as supplying domestic hot water using an indirect tank. It would be either a tank-within-a-tank type or one of the big ones with the boiler water in the containing and a very large coil inside there providing the domestic hot water.

    To ensure it condensed all the time, I would put enough heat emitters to permit the circulating hot water at 130F or lower (preferably a lot lower) to make up the heat loss of the building. I would use as few zones as possible consistent with making the various parts of the house run at the desired temperatures. Unless the heating is radiant in a slab, I might use setback; If some of it is in-slab radiant, I would not use setback with that zone.

    For sure you want a qualified person to design the system, select the hardware, install it, and set up the reset curves, or show or teach you to program them. If you are that person, please read the installation manual (again?) to be sure to do whatever the manufacturer's latest changes suggest.
  • Mark Eatherton
    Mark Eatherton Member Posts: 5,853
    edited August 2012
    If it were me...

    I'd go with an appropriately sized mod con (Lochinvar Knight WHN model) boiler and a reverse indirect (Turbomax) which would keep the mod on in the condensing mode even when doing DHW.

    Sizing is dictated by maximum hourly demand, and or largest individual dump load (think large soaking tub).


    There was an error rendering this rich post.

  • Jack
    Jack Member Posts: 1,047
    Cost is always in play

    First you need to provide a bit more info. 4 baths and a kitchen. What is the lay-out of the four bathrooms? In the master, are there any high flow fixtures? What is that flow rate on that fixture?

    Once you have that info you can lay-out a solution using tankless water heaters. Depending upon the floor plan you may be able to group them together. If the load is really spread out you may want to break up the system. Get asp close to the major loads as possible. I'm a fan of Rinnai;)
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