New Construction Install Tank vs Tankless HWH

Discussion in 'Tankless Water Heater Forum' started by diprivanrn, May 25, 2008.

  1. diprivanrn

    diprivanrn New Member

    Messages:
    3
    I have a new construction under way. 5br 3.5 Bath 4200 heated sq ft. Rough plumbing for 2 Hot water heater with interconnect between systems if one goes down.

    Would you recommend Tankless HWH for this house, as I am seeking energy efficiency. If so, what brands of Tankless GAS HWH's are better than others in the market-I am looking to have great reliability. I have heard of Rheem and Takagi in the market. From what I understand Takagi makes a good product.

    I would like to hear from any of the plumbers out there who install these and people who have had them installed for any problems.

    Thanks,

    Paul
  2. Gary Swart

    Gary Swart In the Trades

    Messages:
    7,302
    Location:
    Yakima WA
    I don't have one and I don't install them but I can tell you they are not what their hype would have you believe. If you are in a cold climate (winter) you will probably not have really hot water. Tankless require frequent cleaning and service which is not cheap. They require mega amounts of power, either gas or electric, and most homes do not have a gas line or electrical service large enough to provide the power and increasing either of them is expensive. When the cost of the tankless and installation is figured in, most studies have shown tankless are not anywhere near the cost saver that they are touted to be. You can search the archives of this forum and read what others have reported yourself, but I would suggest you do a great deal of research and study before you go the tankless route. It's too bad they aren't that good yet, maybe someday they will be but for now, I'd run the other way.
  3. spend the money on insulation

    you are still in the construction phase of the home.....

    Take the difference you are going to shell out for a tankless and
    spend it to put more insulation in the attic..and side walls..

    buy a 75 gallon gas or 80 electric heater....

    install a couple of heater blankets on it and you
    will save more over the long and short haul with almost rouble free
    maintaince.......


    if you live in the colder climates......

    and you really want to go green and maintain
    something that would actually really save you a large amount of energy

    consider putting in a wood burning stove in the basement
    if you have one or boiler...


    that is my plan this winter....



    http://www.weilhammerplumbing.com/houseofhorrors/
    Last edited: May 26, 2008
  4. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,253
    Location:
    Cave Creek, Arizona
    blankets

    install a couple of heater blankets on it and you
    will save more


    How many water heaters have you ever felt that were even uncomfortably warm, which would have benefitted from even one blanket?
  5. jimbo

    jimbo Plumber

    Messages:
    8,997
    Location:
    San Diego
    You would forfeit on of the potential advantages of tankless...small size...if in new construction you did not locate the WH close to the action. i.e. on near master bath, one near laundry. Something like that, depending on how your house is laid out. One of the biggest water and energy wasters is running water down the drain waiting for hot water.
  6. It Usually Takes Two


    Well I have only one on my 75 gallon gas and it does not totally cover the heater completely...and I have never added the extra one yet. I have about a foot gap in the front
    and i need to take it all off and start over with two of them...

    No they have never felt too warm, if you put your hand under the blanket, you can certainly feel the heat that is being held inside the lplastic liner...but it is not much warmer than about 100 degrees.

    It certainly does hold the heat inside the unit and keeps it from
    mixing with the temp of the home
    Last edited: May 26, 2008
  7. edsel_escondido

    edsel_escondido New Member

    Messages:
    2
    My house, built new in 2002, has two tankless water heaters. One is a Bosch Aquastar 125B LP (with pilot) and the other is a Takagi TK1, sold as a Bosch Aquastar 240 (without pilot, requires electricity to run it). Both were purchased new from Controlled Energy Corp. I am satisfied with the 125B, less so with the Takagi.

    Disclaimer: I'm not a licensed plumber so the futzing around I have done with this equipment has been ad hoc. I have not installed any water heater, with or without tank, in anybody else's house.

    The 125B LP was leaky and fussy until I found that the licensed plumber who originally installed it put the control valve in wrong. Once I rebuilt it and installed it correctly this unit has been flawless. If you can rebuild a SU or Zenith-Stromberg carburetor you will understand how the control valve works. I am quite happy with this unit and it has required valve rebuilds on about a three-year rotation. My water is hard and is supplied by a well, treated with ozone in the 5000 gallon tank. The calcium carbonate in the water does not drop out of solution in the heater. It almost certainly would drop out in a tank-type heater because the water gets hotter locally in the tank than it does in the tankless units. This unit has a standing pilot. This negates some of the efficiency gains but see below for my Rant.

    The Takagi is engineered a lot like many modern devices, with a computer and a bunch of electronics. This equipment has been troublesome. I've recently fought a problem with it to what appears to be a successful conclusion: partial lighting of the burner. This required me to remove and clean the burner, which is a bit of a trick on this device. The computer is badly confused by brown-outs and requires re-setting after some of them. The Takagi must have electricity to work. I bought it because I wanted to run a dual shower and could find no heater large enough to do that without it having a powered vent. Since power goes out frequently here, this is a problem. I've thought of cross-connecting the small heater but haven't done it yet.

    If the Takagi isn't fixed by my recent work I am going to replace it with a large Paloma, which requires lower water pressure and has an atmospheric (non-powered) 7" vent, requiring no AC power to run (I believe it has batteries to run the sparker). The twenty Paloma heaters at my favorite hot springs resort receive next to no maintenance and have been there for years. All of them are mounted outside in a place where there is frost but few hard freezes.

    Rant:
    There's a tradeoff between old-school devices and modern ones. The modern ones can be more efficient as long as everything is working, but there are more parts in those and more parts means less reliability. I know of no exceptions. I do not buy appliances that have computers in them. The Takagi water heater was the one exception to my rule and I rue the day I bought it. I will not buy any equipment for my house that has anything more complicated than a discrete SCR in it any longer. Efficiency is good but anvil-like reliability is my first priority and I've never gotten that from modern, computer-controlled, optimized-to-a-fault equipment.
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