pros/cons for tankless water heater

Discussion in 'Plumbing Forum' started by ALPS, Jan 26, 2007.

  1. Jan 26, 2007 #1

    ALPS

    ALPS

    ALPS

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    I'm planning to replace the 40 gallon, 12-year-old,LP water heater that came with the house and want to learn more about the "tankless" type.

    Aside from the obvious pro (endless hot water) and con (expense), what else should I consider? Plumbing, venting, gas supply are not concerns.
     
  2. Jan 26, 2007 #2

    bethany14

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    Sizing is a concern, depending on your hot water demands. Here we only wash in cold water, and don't have a dishwasher, so our demand is minimal. However, if you do wash in hot water, and run a dishwasher, and then go hop in the shower...you see the dilemma. There are high demand systems available, though the price goes up considerably.
     
  3. Jan 26, 2007 #3

    glennjanie

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    Hey Alps:
    The pros are all there is to a tankless system, when properly sized. The higher cost will come back to you each month in lower gas bills because you are not trying to keep the whole 40 gallons hot all the time; vacation, sleeping, while you're at work and I could go on.
    A new water saver shower head and faucets would help tremendously. If your faucets have the areator screen on them, they probably are water savers.
    Glenn
     
  4. Jan 26, 2007 #4

    elementx440

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    i always heard on the am-radio improvement shows that you can get a tax writeoff for using the tankless systems, since they're more energy efficient, i would definately look into it...
     
  5. Feb 18, 2007 #5

    shovelshort

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    I purchased a tankless water heater to replace an existing leaky tank water heater before I looked into the retro fit. I ended up selling the tankless to someone and buying another tank water heater.

    There is a lot involved in retro-fitting for a tankless. Gas lines have to be a certain size, usually larger than existing. Venting is a big issue. Tankless heaters put out a lot of heat and exhaust. The vent has to be larger in diameter and double walled. The run can only be so long according to manufacturer which can be a problem in 2 story homes with the heater in the basement. You can vent out the side, but it has to be so many feet from a window.

    If I were building a new home, I would definitely go with the tankless, but retro-fitting can be cost prohibitive when you are putting one in for utility savings in the first place.
     
  6. Mar 29, 2007 #6

    ALPS

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    shovelshort-- good tips, this would be going into the basement.

    Yes, a tax break is always good. I got a $360 tax credit(out of a possible $500) last week for the new windows and door.

    And lastly, I've heard from a home inspector and a customer service rep at the local utility regarding the lower utility bill. It isn't always what it seems...

    Sure, you don't have to keep 40 to 60 gallons of water hot 24 hours a day, but you do use nearly as much gas heating the cold water coming into your house. Heating large volumes of cold water in a short amount of time takes a lot of energy. Enough to off set your savings.

    Maybe I could use the existing tank to hold the water so it could warm up to basement temperature before going into the tankless system?
     
  7. Mar 29, 2007 #7

    ALPS

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    Proof that more fuel is consumed...
     
  8. Mar 31, 2007 #8

    bethany14

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    Some highlights copied from: http://www.toolbase.org/Technology-Inventory/Whole-House-Systems/tankless-water-heaters

     
  9. Apr 1, 2007 #9

    Square Eye

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    Not enough benefit to convince me that I need one.
    An electric water heater can be set on a timer that turns it off during off-peak usage hours. But in my home, there is no real off-peak time. Starting the cycle over again , warming a cooled water tank may offset the savings anyway. I have a gas water heater, recovery times are very quick. Combine that with the fact that the demand for hot water in my home may come at any time, eh, I'll insulate my tank and keep it.
     
  10. Apr 3, 2007 #10

    bethany14

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    Another con,
    A friend of mine is building for himself in a very small town in Eastern MD. When he got permitting for his tankless they were very apprehensive toward the 'new' technology--they went as far as insisting he needed a pan under the unit, as for a tank. After much debate, they finally realized there was no need for it, but it was quite the frustrating struggle for him.
     
  11. Jan 27, 2008 #11

    apsinkus

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    Wow, never read so much incorrect information in one thread! C'mon, statements like "if it needs bigger supply line it uses more gas" sounds like someone did not pay attention in Physics class. How does a 83% efficient unit uses more than 60% efficient unit?
    Yes, it does require higher volume at a shorter period of time, but the efficiency is where it matters.

    Usual break even point on a tankless water heater for a family of three is 5 YEARS (includes install costs). You will get your tax (state and federal) incentives AND you will see rebates from your gas company of about $400. Gas prices are not going to get any smaller.

    BTW, there are plenty of units out there that can be externally mounted and vented.
     
  12. Feb 28, 2008 #12

    patterrw

    patterrw

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    We have had our Eccotemp Tankless unit for 3 months now, and are very happy with it...We had 1 slight problem at the outset with the control board, but that was remedied right away...ours is mounted on the exterior of the house about 8 feet from the gas meter...our previous water heater was electric 43 gall and 12 years old (Rudd)...this unit, installed, was around $1000, and we qualified for the $300 tax credit on the unit as well as a $300 bill credit from our utility company.

    no need to upgrade gas line or anything

    two of us in the house, built in 1964, 1400 sq ft, 2 baths.
     
  13. May 25, 2008 #13

    B.Thomas

    B.Thomas

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    Well I've got a problem with my Takaji (see another thread here), but don't know what the problem is exactly.

    I didn't install mine to code (hey, maybe that's the problem!), in that we didn't enlarge the gas pipe, as your supposed to do in California at least. But the guy who installed it (a relative of mine with a lot of experience) said there was no need to do so. Don't know if this is true or not.

    But what I like about the tankless is that I save a lot of space. In a place where space is at a premium (NYC or parts of LA or other cities), tankless could be "worth" it on matters other than saving energy costs. I was able to fit a takaji and a stackable washer/dryer where my old heater used to be.
     

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