"In Between" Option(s)?

Discussion in 'Water Heater Forum, Tanks' started by mark_g, Apr 12, 2009.

  1. mark_g

    mark_g New Member

    Messages:
    23
    We're building a new house -- 3½ bathrooms w/showers, (master also has 80 gal tub), large kitchen, dw, etc.

    Use pattern will be uneven--many days unoccupied, zero demand, then we could have a houseful of up to 6-7 adults on weekends.

    Originally, we were thinking that the boiler wd make hot water and have a small 40 gal storage tank that could be fast recovered in periods of high demand. But we are rethinking hvac and the boiler is likely out. We are trying to get the geothermal numbers to work, but I've been forewarned that the desuperheater will not provide enough HW for our needs.

    We are well aware of tankless (we've had one for the past 11 years) and realize that periods of intense usage won't make it unless we start ganging units together.

    So is there a hybrid, with small high efficiency storage and a variable-rate burner-boiler we should be considering? The small storage tank will allow installation of a gravity-fed hw circulation system, and the small tank would take care of high initial demands.

    We have propane, or cd go electric.

    Thanks for your thoughts, Mark
  2. Redwood

    Redwood Master Plumber

    Messages:
    7,453
    Location:
    Connecticut
  3. mark_g

    mark_g New Member

    Messages:
    23
    Redwood--appreciate the link. If it does what it claims, that's exactly what I am looking for.

    Do you have any experience with them? Reliable? Are they readily available? Expensive?

    How does it compare to the AO Smith Vertex or Ruud AdvantagePlus?

    Thanks for the feedback, too!
    --Mark
  4. Redwood

    Redwood Master Plumber

    Messages:
    7,453
    Location:
    Connecticut
    From what I understand they are pricy. I haven't done one yet but I am looking forward to the first. I have heard good things about them from some people who have installed them...

    I'm not a big fan of A.O.Smith....
  5. they are ok

    they are supposed to be pretty nice...

    I odnt know about the propane


    available in my aread for about 2200.... about
    the same as a tankless, only needs pvc pipe like the power vent.

    I too would stay away from the a.o. Smith Vertex

    anything made by them is bound to give you troubles
    and that one looks bad...


    go ahead and be a a test case for one.
  6. mark_g

    mark_g New Member

    Messages:
    23
    Reviewing the specs again, it doesn't appear the Eternal will give us enough flow (the GU32 is rated 5.2gpm at 80º rise/7.0gpm at 70º). That would be enough to run one bathroom at a time, and not what we're seeking.

    I have also read about tank-type "high efficiency" water heaters with 34-80 gals storage capacity and supposedly very fast recovery. Specs boast 95-96% thermal efficiency, and I don't understand how this correlates to the Eternal 86% efficiency rating. These are made by lots of mfrs: American "Polaris"; Rheem/Ruud "Advantage Plus"; Natco "Voyager"; and the often not recommended AO Smith "Vertex".

    Then within these there are various options--stainless, metal or glass-lined tanks, stainless or cuprinickel heat exchangers, power or direct/sealed combustion.

    Would this type of heater work?

    Thanks again for helping me understand the differences so we can chase down the correct type of unit.
    --Mark
  7. chris8796

    chris8796 New Member

    Messages:
    100
    Location:
    Illinois
    How many btu/hr can your propane tank provide? What are your peak non-water heating propane needs?

    What is the flow rate needed at 70 F temp rise?

    How much of a pressure loss can you tolerate?
  8. mark_g

    mark_g New Member

    Messages:
    23
    Chris, good questions.

    I don't have all the technical details, but hopefully this will help answer your questions:

    1000gal propane tank plumbed @high pressure to the house--forget if it is
    3/4" or 1" line. We originally sized the propane system to handle house heating also, but are now moving away from that.

    Peak non-water heating propane needs will be for restaurant range and ovens. We're trying to go geo for heating.

    So most of our propane demand will be for domestic HW. Imagine a weekend houseful of 6 or 7 adults. The 3 bathrooms all have hi flow showerheads (5gpm unless we choke them down), plus kitchen. A 5 gpm shower head at less than 4gpm would not be very decent. Does that mean our peak HW use could fall in the 12-15gpm range with two showers plus kitchen going simultaneously?

    Then again, there will be many extended days of complete inactivity.

    I was hoping for a single unit that could handle the hi flow requirements of all the bathrooms. Perhaps an alternate is to put the two little-used baths on their own HW system? That sounds like a lot more expense, though.

    The orig system designed was a Peerless 80,000 BTU Munchkin that would also make the domestic HW, and a 40gal, high efficiency storage tank. That would give us a head-start during peak water needs, but not lose efficiency.

    Thanks again for feedback.
    --Mark
  9. Beating a dead horse..... Again

    I GOT YOUR ANSWER!!!!!! I DID THE MATH!!!!

    If it is propane,
    Would it not be easier , more simple , less headaches,
    less calculations, less breakdowns....less math ...just to install
    a 75 gallon propane water heater... or two 50 gallons in series????

    then throw a couple of water heater blankets on it and
    live happily ever after...??


    now, if you really want to squeeze that
    extra extra therm out of the equation, get one in a power vent
    and you will save a few cents a month for the little piolit light........




    noooooooooooooo, that is just way too simple and cost effictive

    we cant do that >>> we must somehow go green, green, green <<<<<



    we got to somehow make "space shuttle technology" out of this....


    we must squeeze that last hair of energy out of this no matter
    what the overall long run cost and functionality will be..




    hint, hint, I am being rather sarcastic..............
    Last edited: Apr 13, 2009
  10. mark_g

    mark_g New Member

    Messages:
    23
    MP Mark,

    My issue is why keep 75 gals of water heated all the time, esp when there will be many days, consistently, of complete inactivity?

    I don't fully understand the premise of the high efficiency tank heaters.

    I do understand the flow restrictions of the tankless units--and know that they won't work in this setting.

    In a sense, yes, the simpler may be the better solution. But if a small tank and very quick recovery exist and are energy efficient, then that seems the best solution.

    Or go electric and turn it off when the house is unoccupied?

    Or?

    --Mark
  11. chris8796

    chris8796 New Member

    Messages:
    100
    Location:
    Illinois
    At 15 gal/min and 70F rise is (15 x 8.8 x 60 x 70) is 554400 btu/hr assuming 100% efficiency. That is alot of hot water and energy. I think I would probably be looking at a big tank 120 gallon (main bath + kitchen), plus a tankless unit dedicated to the guest showers. I wouldn't worry about the stand-by losses, they are small potatoes in the scheme of things. You can have it set up to easily turn off the circulating system when your away. You could also add a second tank and use the desuperheater to preheat water feeding the other heaters.
  12. Last edited: Apr 14, 2009
  13. SewerRatz

    SewerRatz Illinois Licensed Plumber

    Messages:
    1,706
    Location:
    Chicago, IL
    Gas water heaters do have a vacation setting.

    A tankless sytsem can work for you but you would need to install 2 units.

    I have looked into the Hybrd tankless units, they are not much better than a tankless unit when it gomes to the GPM ath the needed ΔT rise.

    So in reality your only choice is a tank unit that can really peform for your need that you need to set on vacation if you are not going to be home for long periods. Or mutiple tankless units. May I recomend Bradford White GX-1-55S6SX model. It has a first hour delivery of 200 gallons and recovers 84 gallons per hour. It also draws less BTU's than a Tankless system.
  14. mark_g

    mark_g New Member

    Messages:
    23
    What do you think abt Hi Eff Gas--American "Polaris" BW "Ultra Hi Efficiency" others?

    Thanks for that suggestion--we, too, came to the same conclusion.

    As an alternate, what do you think about the Bradford White EF-60T or American Water Heaters Polaris (either PGC3-34 or PGC3-50) or Ruud Advantage Plus HE45-100 or State Ultra Force SUF60.

    Since it's new construction, installation should be routine. These high efficiency tanks cost more than conventional units but a little less than tankless -- plus, only one is needed to meet the flow rate.

    I don't need a power vent unit--we can direct vent/sealed combustion -- so only one fan?

    Thanks for feedback on this idea. --Mark
  15. Redwood

    Redwood Master Plumber

    Messages:
    7,453
    Location:
    Connecticut
    Mark, is this place going to be seasonal?
    If so what kind of supplied water temp (cold) are you looking at...
  16. SewerRatz

    SewerRatz Illinois Licensed Plumber

    Messages:
    1,706
    Location:
    Chicago, IL
    I have installed the EF heaters in restaurants and bars. They work great, but are expensive. Also the warranty is only 3 years on the tank and 1 year on parts. Here is the spec sheet which shows the warranty. http://www.bradfordwhite.com/images/shared/pdfs/specsheets/800b.pdf
  17. mark_g

    mark_g New Member

    Messages:
    23
    The house will be used year-round, but mostly only 2-3 nights per week.

    We are trying to tie in with geo desuperheater, which shd provide at least warmed water ahead of it (depending on the season) -- otherwise, incoming temp in the middle of January measured 54º.

    With 3+ bathrooms and hi flow (unrestricted) showerheads, first hour use can be high, esp with guests -- but mostly, it will be two or three of us.

    So I am trying to find a happy medium between periods of no use, periods of very high use, and periods of moderate use. Thus, a small-tank HE.

    I know they're pricey, but it seems this is the best time to take the plunge, while we're building.

    I appreciate feedback--thank you all! Mark
  18. Ratz.. why the commercial unit???

    Ratz...Why would you want to install a commercial unit with only a 3 year warranty??? With the fan and power vent service issues that could be possible ? Add the fact I think this fellow wants a propane water heater???

    If it is propane,
    anything in propane and power vent and commercial spells big, big trouble to me.

    their could be some serious service issues some day with something like that.



    If you are still in the construction phase could you not just install a normal double wall 5 -6 inch metal chimmney out the roof ??
    Then all you would have to do is put in one or two normal 50 gallon heaters in series, or you could even buy a couple of higher btu 50 units if you so chose to....

    you could stagger the thermostats one on low and one on high??

    and you can set them both on vacation when you are not there.

    I feel that the more simple you keep this,
    the better off you will be 5-10 years from now

    you dont know how many poeple I talk to that cuss the builder who installed a 75 gallon power vent in their home
    when they could have put in a chimmney during construction.


    good luck either way..
    Last edited: Apr 16, 2009
  19. SewerRatz

    SewerRatz Illinois Licensed Plumber

    Messages:
    1,706
    Location:
    Chicago, IL
    I didn't tell him to install a commercial unit. He asked what we think about itin this post http://www.terrylove.com/forums/showpost.php?p=195865&postcount=14. So I pointed out it only has a 3 year warranty.
  20. Sewer Ratz ....... I stand corrected.......


    sorry, I had not had my 2nd cup of coffe this morning before I read your post......



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