tankless water heater?

Discussion in 'Shop Talk' started by ellebeaux, Feb 22, 2005.

  1. ellebeaux

    ellebeaux Well-Known Member

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    Hi,
    I'm thinking of putting in a tankless water heater in the little house I'm planning. Does anyone have any insights? I'm wondering about natural gas vs. propane, how well does a washing machine work with one, and whether I'll be able to keep the bathtub hot!

    thanks,

    Beaux
     
  2. agmantoo

    agmantoo agmantoo Supporter

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    Many places in Europe and most of Asia use these type heaters. The work just fine and give an endless supply of hot water. I used one for 5 years with no problems what so ever.
     

  3. jgbndaudio

    jgbndaudio Well-Known Member

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    Hello,

    I installed two propane Takagi T-K jr. units last year and as far as the units themselves they've worked flawlessly. If I remember correctly I got them for about $625 each. The only problems I've had were due to bad planning on my part. I used the existing gas line and found out afterwards it’s not large enough to service both units at the same time with the recommended gas pressure. They each have a 3/4" gas inlet and I have them both on the same 1/2" gas line. To compound the problem the unit doing the DHW is downstream of the unit doing the HWBB but this just means that I have to make sure the HWBB unit is off before I jump in the shower or the DHW unit may cycle on and off. This summer I plan to run another separate 3/4" line to the DHW unit to solve that problem.

    We have a fifty-gallon bathtub and I can fill it with water that's way too hot to sit in if I wish. The T-K jr. has a remote available so you can change the water temperature if you desire. I find this useful for filling the tub, as I can increase the hot water temperature up to 167 and crank open the cold water and fill the tub very quickly. Since the remote is waterproof I mounted it right in the shower so that I make sure to reset it before showering. The other thing I can do is shut off then unit before I'm done with my shower and then use up the hot water in the line, so that I'm not paying to heat water that's just going to get cold sitting in the pipes.

    The importantance of properly sizing your unit cannot be understated. With the T-K Jr. I can run either the dishwasher or the clothes washer while taking a shower but not both as my girlfriend found out last week. Since we have a well she really shouldn't have been running all three at the same time anyway. It's the first time in a year that we did that and now we know to not try it again.

    Oh yeah, ignore anyone who says to heat your water with electricity they have no idea what they’re talking about. Using electricity is the least efficient way to heat water.

    Scotty

    PS. You ought to strongly consider having the DHW on a circulating loop that way you don't have to waste a lot of water waiting for the HW to get to the tap. I also plan on doing that this summer.

     
  4. twohawlks

    twohawlks Member

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    I have a question about using tankless heaters with hard water.
    The water here is high in mineral content and water heaters have a short life (4 to 5 years) and they need to be replaced because of deposit buildup.
    Does anyone know if tankless heaters would be any better or worse ?
     
  5. mtman

    mtman Well-Known Member

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    yes they are calsium deposits and as far as running 2 separet lines i would have run a 1inch line and branch of that with 1x3quarter in. tees the 1inch line will carry enough gas for resivouir they also sell units with a turbo seconddary burrner it will carry 2 showers a washing machine and a dish washer all at the same time the second burber doesnt hick in untill needed
     
  6. TheBlueOne

    TheBlueOne Well-Known Member

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    Theoretically tankless would be better because you would only have to change the heat exchanger. But that assumes you can get parts and that the parts are attractively priced. With some things it's cheaper to buy the whole unit new than to buy replacement parts to fix the old one.

    Our hot water heater will be a year old in April. Last year about this time I agonized and researched for weeks over whether to go tankless or not. What I ended up doing was putting in a high efficiency power vented 40 gallon tank unit. This water heater has 2" of insulation around the tank (R-20 value) to reduce standby losses and electronic ignition to reduce pilot losses. It vents through the wall which eliminates the stack losses from being hooked to the chimney. The water heater is a GE brand unit came from Home Cheapo where the price was $335 for a LP version. Get a Home Cheapo credit card (I did) and that knocked 10% extra off for a net price of $301.50 plus tax.
    That compares to $870 for the tankless water heater I was considering. The tankless is more efficient but even with my family of 6 I would be waiting 15-20 years to see any payback.
    Researching the web, a lot of people like their tankless heaters and quite a few didn't. The main problem was lack of repair parts because they don't yet have much market penetration. Home Cheapo sells Bosch tankless hot water heaters but NO parts. With my high efficiency tank unit (that only cost me $300) I can get parts at any one of the local hardwares, department stores, Lowes, etc. Propane usage, which I track with an Excel spreadsheet, is about half what it was with the old water heater which was about 12 years old (and working fine) when i took it out last year.
     
  7. mtman

    mtman Well-Known Member

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    if every month you drain 2 gallons from the bottom valve you can add 2 years to your water heater gets the sludge and rust out thats what causes it to rot out
     
  8. Runners

    Runners A real Quack!

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    "....Oh yeah, ignore anyone who says to heat your water with electricity they have no idea what they’re talking about. Using electricity is the least efficient way to heat water....."

    In Virginia, with the cheap .034per KWH electric rates (.05 with all taxes) and high gas prices, electric power is still more cost efficient than either LP or NG.

    BTW, what is the current rate in New York state, before and after all applicable taxes and fees? When I lived in Wisconsin, it was +.07KWH, (over .10 with all fees and taxes) - which made LP @ $.52 a gallon a super deal. Now, the price of LP is 3x that, and electric rates have hardly moved.

    Dollar for dollar, solar water heating looks pretty appealing! :D

    Back in the early '90s, we installed several 120v point-of-use electric water heaters (flow rate regulated, 70 degree temp rise), as preheaters for coffee makers and hot water dispensers. At just $150 each, and the time to run a branch circuit + breaker, they can be plumbed into any 3/8 supply line for a sink - and they do work, trouble free, no liming up. Very small, about 12x6x4" and mount directly to the wall under a sink.

    "electricity is the least efficient way to heat water." - was that in dollars, or are you trying to compare KWH to BTUs of LP? :)
     
  9. Runners

    Runners A real Quack!

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    Had to dig for this, but get your energy bill in hand and plug in a few numbers.

    http://calc.usepropane.com/calculator/

    If you're curious, Residential LP is listed @ $1.69 today (no taxes or fees included)
    .... my electric is still $.051 per KWH (all fees and taxes included)
     
  10. ellebeaux

    ellebeaux Well-Known Member

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    Thanks everyone for answering my question - I've only posted to this website twice and I thought it would give me 'instant notification by email' and forward the emails to my address so I'd know if anyone answered. I was disappointed that no one did so I didn't come back to the site until today.

    Okay, next question: Is a solar water heater a reasonable idea in Virginia??? What kind of backup system would be better? I guess a tankless water heater would work if it had a thermostat on the intake.

    I'm thinking of building a 500-750 sq ft home near Charlottesville but am having a heck of a time finding land that I can afford. So I may end up having to buy a small home instead and wait on my dream of being totally self-sufficient. Meanwhile I'm trying to learn all I can that would be applicable to either situation. I like the idea of building my own home better as I could do everything 'right' (ha!) the first time rather than redoing a whole energy/electric/septic/water system.

    Anyway, thanks for the input and I'll check in more often!

    Beaux
     
  11. rambler

    rambler Well-Known Member Supporter

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    I only skimmed the many replies, but here is something worth checking into:

    When our old cast iron electric water heater gave up the ghost, our electric utility (an REA) has a program where they will replace the water heater with an 80 gallon electric model with lifetime warrenty for $120. Including installation. In exchange, they put a controller box on it that allows them to turn it off during the day, or otherwise limit it's use during high-peak demands. In effect they control these things to let them level off power demands, and keep electricity flowing smoothly. That is a rather large heater, sized so it stores hot water until the next heating period. I only had warm instead of hot water when someone didn't close a fauccett overnight......

    This is a great deal, a water heater of that quality is well over $500 sitting in a store, not counting delivery, installation, etc. It is pegged way over on the most efficient side of the efficiency label.....

    I'm running the house, deep well, and farm with 40 head of cattle for $50 or so electric bill every month, so stories about electric heaters costing too much are not always true.

    I would look into this in your area, many power companies are legally forced to 'reinvest' 1-2% of their income into such types of programs these days. Even replacing large electric consming appliances/ lighting with more efficent models will get you a cash rebate from the electric company here - if you are smart enough to go apply for it.

    --->Paul
     
  12. Runners

    Runners A real Quack!

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    We're down near Chatham, VA. Solar has been on our mind for the last 5 years, and using up one of those "West Virginia State Flowers" looks really tempting.

    If I had the link, I'd post it - to the national weather service surveys. It gives you estimates based on real historical records, dealing with expected days of sunshine, average wind speed, etc., across the whole state. Because the mountains moderate our weather differently across the state, you'll need to look at specific maps for your area. I wanted to go with wind power, but I haven't got the wind speed often enough to make it worth while.

    Solar, for my area looks really promising, and probably is for Charlottesville as well.

    Now, if you happen to live on Afton Mt. ..... or have a small creek.... MICRO HYDRO!!!!

    Check into HOMEPOWER.COM for really useful articles on SOLAR and WIND power.

    As far as electric vs propane power water heaters, I want BOTH, in big tank models. Right now, electric is a BARGAIN, propane isn't worth running - but that can change. Is it wasteful? In my case, we're a family of 10, our water usage is HIGH, and the water heater is the biggest part of our electric bill, higher than the AC or stove. (this IS VIRGINIA, remember). The SOLAR panels can preheat the water in both heating tanks, basically the tanks give me more storage.

    Since you live in VIRGINIA, you know is was plenty sunny today, and in another month you'll start the spring/fall cycling of heating at night and AC during the day. +50 degree temp swings are common...

    Good Luck!