Requesting advice on tankless hot water heater.

Discussion in 'Tankless Water Heater Forum' started by shaps, Apr 20, 2014.

  1. shaps

    shaps New Member

    Messages:
    7
    Location:
    Pittsburgh PA
    I currently have a 40 gallon Rheem hot water tank that needs replaced asap. I am trying to decide if a tankless water heater would be good for me.

    My home is a typical split entry (two and a half baths) and is all electric. There are currently 3 people living here but could be four if my daughter moves home. We have 2 showers and a tub (bathrooms are back to back and are almost directly above the hot water tank. The hot water tank is in the laundry room (below the kitchen). The hot water pressure is very low going into the washer so it takes a while to fill. The kitchen is next to the bathrooms and I do have a dishwasher (newer Bosch).

    Never are two people taking showers at the same time but my son does take long showers. We live in Pittsburgh, PA so it does get cold.

    I would love to save money, be more environmentally friendly and have a less cluttered laundry room, but I don't like waiting more than a few seconds for hot water to start. Would a tankless be a wise choice for me and, if so, what specifically should I look for? If not, I would probably be considering a Rheem tank. Thanks in advance.
  2. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,313
    Location:
    New England
    If you cannot use anything but electric, do not use a tankless system (except, maybe for a single point of use like for a single sink)! You'll likely need to pay for a larger power drop from the power company, a new panel, and wiring to the unit itself. A good sized gas tankless is in the order of 199,000BTU. To get equivalent heating capacity on an electric tankless, you'd need about 243A and nobody makes one that big for residential use. As a result, their performance is less (less hot water/time) because they do not make them that big. One BTU=0.293 W/hr.

    A tank can work if it has enough time between uses to restore the set temp (often, many hours, rather than the time it takes for the water to pass by the heating element in a tankless). The standby losses on an electric WH are pretty low, so if you need more, and can't use gas, get a bigger tank.
  3. shaps

    shaps New Member

    Messages:
    7
    Location:
    Pittsburgh PA
    Thanks very much for the info Jadnashua. I am in the dark about these things. Our electric company does give us a residential heating rate so it's not too bad. We have an electric heat pump and it's sufficient but I think even that is better suited to a warmer client. So even with having a 220 line we would still need a new panel to handle the tankless system? That's definitely a deal breaker for me. Thanks again for sharing your knowledge.

    Any recommendations on a good hot water tank? I was thinking another 40 gallon Rheem.
  4. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,313
    Location:
    New England
    Don't mistake volts for power...most homes have 240vac coming in, but a typical home may only have 100 or maybe 200A service (my sister's old house has all of 60A - way too small for today's typical home). To equal the heat of a single 199,000BTU gas tankless would require the 200+ Amps all by itself, more than a typical house has available for everything else in the place. You can see what your max power available is by the main circuit breaker in your panel...likely somewhere between 100-200A.
  5. shaps

    shaps New Member

    Messages:
    7
    Location:
    Pittsburgh PA
    I see. Yes, I did misunderstand. Thanks for the clarification!
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