General Questions about 2 Tank Heater System

Discussion in 'Water Heater Forum, Tanks' started by Jimmy314, Oct 9, 2010.

  1. Jimmy314

    Jimmy314 New Member


    We have a home with two 50 gallon electric water heaters. They are both working but very old (27 years). The house is 3 bedroom 2.5 bath 2000 sq ft. One heater is in the laundry room and the other in a closet by the bedrooms.

    Im sure I could crawl under the house to check, but I was wondering if they would typically be plumbed together or are the hot water systems separate? If they are separate, it seems that the one in the laundry room is too big as it would only feed the dishwasher/kitchen sink and the laundry machine. Maybe a small tankless electric heater would be better here?

    The second water heater feeds two bathrooms and is working okay but the temp is not consistent. I changed the thermostat a few years ago, but the problem has returned. AT 27 years old we are fine with replacing this unit. We figured we would look for the most efficient regular replacement. There is no room for hybrid and Im not sure if we want a tankless unit for bathroom/showers after reading the consumer reports.

    We do have natural gas at the house, but we do not want to convert due to high installation cost.

    Any advice on what would be an efficient upgrade to our system would be appreciated.


  2. Terry

    Terry Administrator Staff Member

    Bothell, Washington
    A tankless for electric would require work at the main panel and new wires run to the heater. They use a lot more power then the storage type tanks, which heat slowly with little power needs, and then store it.
    If you are going to "fry" your water, you need an electrician first.
  3. Jerome2877

    Jerome2877 In the Trades

    Try closing the valve to one of the tanks and check the fixtures for hot water, this will tell you if they are plumbed seperatly.
  4. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    New England
    For hardware longevity, the electric WH often last longer than a gas one. Whether it would end up less expensive to operate it depends entirely on your local electrical rates verses gas. In most places, a gas WH is a lot less expensvie and has a faster recovery rate than electric. Since it is very unusual for either an electric and much less a gas unit from lasting that long, you would likely end up replacing the gas more often, which would eat into the energy use cost differences. to maximize the longevity, replace the anode rods periodically and flush the crud buildup that settles on the bottom.
  5. Thatguy

    Thatguy Homeowner

    My gas water heater used 31 therms of energy in one month and cost the two of us $60.
    If it were electric at $0.15 per kwh it would cost me $136/month for this same 31 therms.
    Let's say I had an elec. heater and routing the gas pipes costs $2K.

    $2000/($136-$60) = 26 months for the conversion to pay for itself.
    Try your own numbers.

    People move to a new house in 7 years on average, and this is less than the service lifetime of either type of heater.
    Last edited: Oct 10, 2010
  6. Jimmy314

    Jimmy314 New Member

    Thanks for the replies. Good idea of closing off one of the tanks to see if they are plumbed together, much easier than crawling under the house. Our electric bill is rarely over $90 and based on the costs it appears that the electric tanks are still the best choice. The break even for switching to natural gas would be many years.
  7. hj

    hj Moderator & Master Plumber Staff Member

    Cave Creek, Arizona
    Without testing the system there is no way for us to tell you which way it is piped, since there is no "standard" way. It depends on how the plumber was feeling that day.
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