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on demand electric water heater

Discussion in 'Home Power and Microgeneration' started by gcroix, Feb 2, 2005.

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  1. gcroix

    gcroix Guest

    Hello all,

    I'm not sure this is the right newsgroup, but I'll give it a shot. I
    currently have a small electic run of the mill water heater. I'm thinking
    of replacing it (output is starting to decline) with a electric 'on demand'
    water heater. Has anyone out there done this, or do you have one? I have
    questions about where to place it (concerning distance from breaker box),
    and whether to buy one for each sink, or to buy one for the whole house.

    Thanks in advance,

    Gary C in EC, NC
  2. m Ransley

    m Ransley Guest

    On demand take alot of power, A Bosch whole house unit needs 120 amp
    dedicated. For me Gas is the only way, im in the midwest and
    electricity is 3x the cost of gas.
  3. Willcox

    Willcox Guest

    They make them for RVs, but they still take a lot of power.
  4. Mel

    Mel Guest

    gcroix a écrit :
    I've lived in houses with on demand hot water before, and I would rather
    shower cold than use one again. Uncomfortable.

  5. m Ransley

    m Ransley Guest

    Modern electronicaly controled Tankless are great Ive had one 2 yrs No
    complaints from anyone.
  6. Steve Spence

    Steve Spence Guest

  7. Steve Spence

    Steve Spence Guest

  8. Steve Spence

    Steve Spence Guest

  9. m Ransley

    m Ransley Guest

    I had a good electric tank Rheem 3 yrs old. I was paying 30- 40$ a
    month at .125 kwh for it . I put in a Bosch Aquastar pilotless Battery
    ignition 117000 BTU Ng unit keeping the electric tank as a Pre tempering
    tank. Costs to do 5 loads of laundry , cook 3 meals a day and HW now is
    6-7 $ a month in summer. I pay apx 1$ a therm. Payback is very short
    for this unit. I agree electricity for 99% of the US is not the smart
    way to go on Kwh vs Ng comparison costs. Plus the 120 Amp Bosch may
    require you upgrqading your service. Rinnai has higher efficiency than
    Bosch or Takagi. Rinnai is worth a serious look for Gas tankless.
  10. Steve Spence

    Steve Spence Guest

  11. m Ransley

    m Ransley Guest

    Look into Rinnai gas tankless. I believe they are apx 5% more efficient.
    Bosch and Takagi run 82-83%
  12. m Ransley

    m Ransley Guest

    I was not clear or correct on an earlier post , I have a Bosch tankless
    Gas, but have heard their Electric tankless operates with the same
    quality as gas. The electric tankless needs 120 Amp dedicated. Truely a
    hog. My electric is 3x the cost of Ng so I would never consider it as
    few should that have higher electric costs. If I was to do it again Id
    look into Rinnai as its efficiency is higher other than that the Bosch
    gas works great and needs no AC line as it is Battery ignition,
    Batteries are on their second year and recently tested good, 2 regular D
  13. Steve Spence

    Steve Spence Guest

  14. Luv Hobitses

    Luv Hobitses Guest

    Why? What were your objections? The delivered temp of
    the water? Volume? Power and $$$ consumption?
  15. Mel

    Mel Guest

    Luv Hobitses a écrit :

    Well, it may be because it was a rented house and the hot water system
    ws crap but:

    The temperature was unstable and would cycle cold warm hot cold warm hot
    with a complete cycle in about 4 minutes. This meant getting under the
    water only when it was on the warm phase - to avoid freezing or getting

    The other place I lived in with on demand hot water was uncomfortable
    because it cycled (not as drastically) but also becasue it made a lot of
    noise - so if someone else had to get up early, you ended up being woken
    up as well.

    Maybe I was just unlucky?

  16. m Ransley

    m Ransley Guest

    Mel you had 2 units in need of repair or 2 cheap units. That can happen
    in rentals, you should have demanded a repair - remedy. My Gas goes
    from 1/2 gal - 5 gpm with no temp change and electrics I have tried the
    same. There is more to break on a tankless, but they save allot of
  17. Mel

    Mel Guest

    m Ransley a écrit :

    I guess I didn't know enough to know that the units we had were broken
    or cheap - I just thought they were all like that!

    Of course, it wouldn't have been a problem if we took baths, and it
    wasn't to hard to do the dishes...


  18. Before replacing the HWH, have you performed any basic maintenance?
    Have you flushed it to remove crud? Does the sacrificial anode still
    exist? Do you have hard water? Scale buildup on the elements acts as
    an insulator, and replacement elements are cheap and easy to install.

  19. Me

    Me Guest

    Geez, what a DUFUS, Anyone with a gradeschool education knows that the
    heat also goes into the surrounding air as well. Any heat lost to the
    surrounding enviorment is considered a loss term in the efficincy of the
    water heater.

    Me who knows a morooon, when I read one........
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