On-demand water heaters

Discussion in 'Green Energy and Sustenance Living' started by bethany14, Sep 8, 2006.

  1. Sep 8, 2006 #1

    bethany14

    bethany14

    bethany14

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    Anyone know about these? A friend of ours put one in the new house he's building. He hasn't moved into it yet, but we expect he will in the next few months. It makes sense to me, to heat water as you need it heated, rather than keep a big tank full and heated all the time.
     
  2. Sep 9, 2006 #2

    glennjanie

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    I think they are great! I believe it is the comming traditional water heater. No energy is used unless the water is turned on, no more running out of hot water, shower forever if you want; but it won't cost you anything unless it is in use. They simply hang on the wall in the utility room; leaving that much more space on the floor. Hey, its the best of both worlds!
    Glenn
     
  3. Sep 10, 2006 #3

    Sven

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  4. Sep 12, 2006 #4

    bethany14

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    So, do you go gas or electric? Personally I'm trying to limit the fuels I need, and I'd love to go solar. How about you guys?
     
  5. Sep 13, 2006 #5

    glennjanie

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    Hello Bethany:
    Solar water heating was patented by a man in the North East. The February day the patent office was to view his invention was overcast and he asked for another day. They said "No, today is your day, it may be a year or more before we can come back". They came in, he started his pump and the water came back 20 degrees warmer than when he sent it out!
    The only thing about solar is, you have to get used to wide temperature swings. But, you sure can't beat the energy cost.
    Glenn
     
  6. Sep 11, 2007 #6

    Boston

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    We had a tankless heater in a former house, and never ran out of hot water. Everything was oil-based in that house, so NOT having to heat a huge tank of water was a nice break on the energy bill.
     
  7. Sep 21, 2007 #7

    LoneJeeper

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    What's the break even point, i mean after how long does it pay for itself?

    Most of the green (especially solar) solutions I see today have a break even point of over a decade.

    Some solutions I have seen need replacement parts every 8 years that break even every 10.
     
  8. Sep 21, 2007 #8

    glennjanie

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    Hello LoneJeeper:
    Comparing a quality tankless water heater to a quality, efficient, 10 year warranty tank type water heater would give you a little less than 3 years to pay-back.
    Glenn
     
  9. Sep 24, 2007 #9

    phreaq

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    I am looking to go from an electric water heater to one of these new tankless heaters myself. Our area just got natural gas, but I have read many places that an electric tankless will cost less to purchase and operate than a natural gas tankless, due to the effiecency difference (~80% compared to 98%)

    Can anyone else confirm this?
     
  10. Sep 24, 2007 #10

    glennjanie

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    Electricity comes to your appliances at 98% but they don't mention the 40% effficient steam turbine that made the electricity. Believe me they charge you for the other 60% they wasted too.
    Natural gas is the way to go in your place, although oil heat produces more btu's per dollar than any fuel. You will save a bundle by using the natural gas, tankless heater.
    I use a geo-thermal heat pump to heat and cool my house and hot water is a by product, summer or winter; it uses the latent heat from the compressor which runs for heat or cooling.
    Glenn
     
  11. Nov 16, 2007 #11

    kentaysdad

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    hello all I am considering going with a tankless but was told by a local plumbing retailer that i would give up water pressure. does anyone know if this is indeed the case?
     
  12. Nov 17, 2007 #12

    glennjanie

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    Welcome Jon:
    I don't think you will see a noticible loss in water pressure. The tubing in the demand heater is the same size we use on the outside, but there is quite a bit of length added to it. Maybe you could see a difference with pressure gauges but hardly notice it otherwise.
    I think it is so wise to heat only the water you are using rather than having 30 to 80 gallons kept hot even while you sleep or are gone on vacation. I think this is what the young people call a 'no-brainer'.
    Glenn
     
  13. Jan 28, 2008 #13

    TheFentonGuy

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    I've been thinking of doing this hear in the next year or so to our house. We currently have a gas hot water heater, rented from Vermont Gas. The rental alone is $130/yr. I was thinking of this as an alternative, but my plumbers who have done a number of installs with the recent "green" movement has told me that the only major draw back is that these units only work with the hot water on full blast. Is this true? Or is this just a first generation limitation? I don't think I want hot water on full blast when I want it. I wash dishes at night and would hate to have hot water on full blast instead of partially turned on.

    Anyone hear of anything different?
     
  14. Feb 13, 2008 #14

    patterrw

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    My wife and I had an Eccotemp 40-H Tankless water heater (Nat. Gas) installed in our House on Dec. 15th...The unit (~$700) and about (~$350) for installation. I ran the electric (15amp GFCI) to save a little money...It is mounted on the exterior of the house, here in SC.

    All in all we are very happy with the unit...It freed up some much needed room in our 1500 sq ft house, and we are very please with it, setting the thermostatic contol to 115 is PLENTY hot...we chose this setting because you can basically get in the shower and turn the hot water valve full on, and just crack the cold water valve a little bit.

    problem: Location, Location, Location - We located the unit on the far end of the house, about 4 or 5 feet from the gas meter. This puts it a good 40 feet from the washer and kitchen sink (and dishwasher when we add one!) The old tank was on the opposite side of the house, about 35 feet from the full bath...this meant that when you went to take a shower, alot of cold water flowed before it got warm....now, when you go to wash dishes, alot of cold water flows until it gets warm. The pipes under the house are not insulated, and I think that would help to some extent.

    We have had no problems with water pressure. Our old water heater was 43 gal Rheem circa 1995, and we were glad to replace it with something more efficient.

    a potential solution to our problem is to add a small (10 to 15 Gal.) electric water heater underneath the kitchen sink. the tankless unit would do the heavy lifting (bringing the 'outside' water from water temperature from whatever it is up to the 115 degrees), which is where I believe the modern tanked water heater uses much of it's electricity. This small pony tank would feed the kitchen, laundry, dishwasher, and 1/2 bath (currently being planned) for that side of the house....another option I think would be a small under cabinet electric tankless water heater
     
  15. Feb 13, 2008 #15

    glennjanie

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    The tankless water heater has a 'flow-meter valve' in it that tells the controls that water is moving and thus turns on the heat. You may not have a sensitive enough flow meter and miss out on the turn on. You may also need a 2 stage water heater of some kind. It will boil water on low flow if the heater is running wide open.
    They are becoming more and more sophisticated (and higher priced) as we use them.
    Glenn
     

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