tankless water heaters?

Discussion in 'Archived Threads 2001-2004' started by Craig Robertson, Feb 3, 2002.

  1. Craig Robertson

    Craig Robertson Supporting Actor

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    my conventional water heater is on it's last legs. anyone have any experience with tankless systems, like the Bosch AquaStar at www.controlledenergy.com? or any other product?
    i'm looking for both good and bad.
    Thanks!
     
  2. Scott L

    Scott L Producer

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    I posted on this a loooong time ago so now the thread is deleted. The general consensus was that it's just not worth it because it feeds off the incoming cold water pipe to your house, meaning that whenever you use hot water your cold water pressure dramatically decreases. For members with families this wasn't a good thing but for couples or singles it wasn't so bad.

    Hopefully they've come up with some new technologies since then.
     
  3. Craig Robertson

    Craig Robertson Supporting Actor

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  4. Scott L

    Scott L Producer

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    Yea but the tank doesn't get filled up as fast as its taken out. From what I understand a tankless heater is much more demanding on the water pipe to your house, designed for high output.

    Hopefully someone who actually has one or has used one could tell you the pros/cons more.
     
  5. Craig Robertson

    Craig Robertson Supporting Actor

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  6. JohnRice

    JohnRice Lead Actor

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  7. Craig Robertson

    Craig Robertson Supporting Actor

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    Bosch has models available in electric, natural gas, or propane.

    my current water heater is electric, but i have gas coming into the house. the water heater sits next to the gas furnace. the two most likely scenarios are replace with a conventional gas water heater or a gas tankless heater.
     
  8. David Werner

    David Werner Stunt Coordinator

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    I thought about going this route however if you have a family with a high demand for hot water it is best to have two of these units such as one for the Kitchen and bathroom and one for the Laundry and bathroom. The reason being is that the demand for the quantity of that high of temperature of water for the entire house typically exceeds that of one unit. I believe last I looked that multiple installations was on some of the manufacturers recommendations. I'm all for it, by the way I still can't figure out why (At least none I've seen) the manufacturers don't come out with a composite tank to avoid rusting the bottom! Let us know if you go the tankless route and how it works for you. Good-luck.
     
  9. Craig Robertson

    Craig Robertson Supporting Actor

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    thanks, David.

    as far as the composite tanks go, i think it's not so much rusting out as it is sediment build up. on a gas unit it builds up on the bottom and insulates the water from the flame, decreasing efficiency. on electric it does the same by isolating the water from the lower element.
     
  10. Todd Hochard

    Todd Hochard Cinematographer

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    Personally, I'd go the gas tankless route. Gas is a more efficient way to heat water than electric.

    The concept is perfect- heat ONLY the water you need. With a tank, a lot of the heat is wasted to ambient losses. This will place no higher water demand on your cold water system than any other hot water heating system (I'm not sure where the idea that it would came from).

    Size it right- just like you would a tank. And I've seen some with long (15-20 years) warranties, so seek those out.

    Todd
     
  11. David Werner

    David Werner Stunt Coordinator

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    I think the sacrificial (I think Magnesium)metallic rod should take care of that. Grant it the sediment will collect on the bottom but surely would not be as dramatic of rust effect as it would a composite base, efficiency aside. I know that we all practice our maintaince on our water heaters (Yeah right!). The thermo-coupler on our 40 gallon is going soon and this topic is sure tempting me to reconsider the tankless system, it's all about savings and makes perfect sense.
     
  12. Scott L

    Scott L Producer

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    Ever wonder why most homes still use tanks if they cost more? When I worked in construction every new house for Ryan Homes had a hefty hot water heater that was a pain to haul into the basement. I wonder why they just didn't install 2+ tankless systems as David recommends. Maybe a deal with the electric company. [​IMG]
    We have a 52 gal and the bottom element seems to be dying out more often than it's supposed to (the tank is a little over 10 yrs old). Craig tell us what you think of your new tankless choice when you get the chance.
     
  13. Todd Hochard

    Todd Hochard Cinematographer

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  14. MickeS

    MickeS Producer

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    What I'd like to know is why some people call them "hot water heaters" and not just "water heaters". Isn't it sort of implied that a water heater makes water hot? [​IMG]
    /Mike
     
  15. Bill Catherall

    Bill Catherall Screenwriter

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    Yea Mike. I've often wondered why some people like to heat up their hot water. [​IMG]
     
  16. Jay Heyl

    Jay Heyl Stunt Coordinator

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    I was just looking into getting one of the Bosch tankless heaters. Most of the positive points have already been mentioned. The biggest negative for me was the requirement for a 5" flue. A standard gas water heater has a 3" flue. If you don't already have a 5" vent pipe your cost could go up considerably. (This is what killed the deal for me. I live in a condo that has a 4" vent pipe. No way I could get that changed to 5".)

    The other big negative is that rather than heating the water to a fairly constant temperature, the tankless heater provides a fixed temperature gain for a given flow rate. So, at 2GPM you might get a 90F temperature rise, at 4GPM you'd get maybe a 50F rise. Depending on where you live, the difference between winter and summer could make a big difference too. (In Southern California the cold water might be 55F in the winter and 75F in the summer. Northern areas would tend to be more constant because the water mains are buried deeper where the temperature stays about 55F all year.) Anyway, depending on the time of year and the amount of hot water being used at any given time, the temperature of the water coming out of the tap could vary by 50F or more. You might get 110F or you might get 165F.
     
  17. Craig Robertson

    Craig Robertson Supporting Actor

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    there are now two of the larger models that use a 4" flue. the 125FX and the 240FX. they are using a powered vent to get more flow thru the smaller flue.

    it also looks like they now modulate the gas flow/flame size to regulate a constant output water temp.
     
  18. Jay Heyl

    Jay Heyl Stunt Coordinator

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    Thanks for the info on the 4" flue. Unfortunately, that model is listed at $899. With installation I'm sure I'd be looking at over $1100. The top-of-the-line 50 gallon model from Home Depot, with 12 year warranty, would be about half that (also installed). I really like the idea of having a serviceable unit that will probably last 25 years or more with a little care, and the thought of not having to worry about another water heater tank springing a leak is a big plus, but I'm not sure these add up to double the cost. Maybe Home Depot could get me the power vent model for less than $899.

    BTW, where did you find the info modulating the gas to regulate the temperature of the heated water? I looked on the site you mentioned in your original post and couldn't find anything that addressed this.
     
  19. Craig Robertson

    Craig Robertson Supporting Actor

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  20. DaveBB

    DaveBB Supporting Actor

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    I've talked to a couple of plummers and they were all againts them for home use. Tankless water heaters are best for a situation where you have a sink/bathroom FAR away from where a tank water heater can be placed. For example a garage or large warehouse.
     

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