Replacing two independent water heaters with one new hybrid water heater?

Discussion in 'Water Heater Forum, Tanks' started by louxwe, May 8, 2014.

  1. louxwe

    louxwe New Member

    Messages:
    2
    Location:
    AZ
    So I was inspecting my very old 50-60 gal electric water heater and wanted to replace it with a new hybrid electric water heater, only been in the house for two years so after some inspecting I had some questions since the house seems to have been plumbed up very oddly. I have the one large 50-60 gal electric water heater in the garage workshop, and another 30 gal water heater in the laundry room on the exact opposite side of the house. I assumed that the large one ran most of the hot water and maybe the small one was added later to help run the kids shower and laundry. So I thought I could just replace the larger electric with a nice new Hybrid electric (GE, 50Gal) but in playing with turning off the hot water last night it appears that the small 30 gal heater runs hot water to the kids/guest bath shower, the laundry washer, the kitchen for cooking, and the dishwasher. And the large 50-60 gallon seems to be piped up independently and only runs the hot water for the master bedroom shower and the 1/2bath sink. Can anyone explain why in the world it would have been piped up that way. I really can't justify paying $1100 for a new hybrid water heater with 50 gal capacity that will then only have to run hot water basically to just the master shower (esp. since I take a shower in the AM and my wife showers in the PM). I don't think I would be able to get the energy savings of a hybrid since most of my hot water usage is on the other smaller 30 gal basic electric heater (which by the way we have never really had any hot water shortage issues.) I could replace both heaters with new hybrid but most of them are 50 gal units at the smallest so now I would have to invest $2200 in two new 50 gal hybrid units for a total of 100 gal and yet even now the smaller unit gives us enough hot water.

    I would really like to buy just maybe one 80 new hybrid to run the whole house but it doesn't appear that the hot water pipes on the East and West side are connected. SO...

    Would it be possible/good idea to just get one 80 gal hybrid hook it up in garage and try to find some way to run a pipe from that side of the house over to the other side of the house and hook into that hot water loop and just get rid of the smaller unit??? Only been in the house two years (built in 1990) and I have no idea where the pipes run at all. Or would that be too hard/costly and would I lose too much hot water pushing it over to the other side of the house. or

    I could just replace the current 50-60 gal with something more like a 20-30 gal (maybe tankless) to basically just run the hot water for the master shower (in our case specifically it only really needs to have enough to run one shower), an then maybe at a later date replace the other 30 gal heater in the laundry room with a 40-50 gal hybrid. I expect that side to be the one that will have more demand since it is possible that we are cooking, running the dishwasher/laundry and kids taking shower all at one time.

    I think one company makes a 40gal hybrid but I think thats the smallest hybrid out there, I suppose I could just replace both with the 40 gal hybrid wired independently but that would cost $2200 for two hybrids and surely would not be as efficient as one 80 gall hybrid that would only cost $1200, even if I did have additional cost for reworking pipes and plumbing??

    Not sure why it was ever plumbed up this way to begin with... any suggestions?

    Thanks, Bill
  2. louxwe

    louxwe New Member

    Messages:
    2
    Location:
    AZ
    Any thoughts?


  3. Dana

    Dana In the trades

    Messages:
    2,866
    Location:
    01609
    Only you are in the position of doing the archaeology necessary to figure out where the pipes run, and how to convert it into a single hot water distribution system. On many slab-on-grade homes often times much of the distribution will be under the slab, but that's not to say you couldn't reasonably run a section of hot water distribution plumbing in the attic to connect the two sides of the system. If they're easy to hook up, a demand-switch recirculation system for getting the hot water from one end to the house to the other quickly may be "worth it", but whether it's really necessary is anybody's guess. How far is it from the garage tank to the nearest tap served by the other HW heater?

    If the 30 gallon system is capable of filling the biggest tub a 50 gallon heat pump water heater would probably cover your loads, but if you have a big soaker tub or would regularly be running multiple simultaneous showers the 80 is going to be a better bet. A decent sized electric tankless big enough to fill a tub at a reasonable rate is a HUGE instantaneous electrical load, and would require it's own 100 amp 220V breaker- it's a terrible "solution" that may even require upgrading the service capacity to the house, and would save less than $5/month in power use compared to a cheap standard electric tank. You'd be better off spending the money adding another couple of PV panels onto your grid-tied solar array to (more than) cover the standby loss of a tank than buying a tankless hot water heater, even if you DIDN'T have to upgrade the power drop to the house. A small 20-30 gallon electric tank isn't really any cheaper than a 40-50 gallon tank, and has similar standby losses to the standard sized tanks. It makes sense to spend money when it's better than doubling your efficiency with a heat pump, even if it means adding another $300-500 to plumb the two sides together and add a recirculation pump to keep from wasting water & time.
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