On demand /tankless water heaters?

Discussion in 'Michigan Homesteading and Home Improvement' started by d_rek, Oct 19, 2020.

  1. d_rek

    d_rek

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    Considering going tankless after our electric water heater bites the dust. Anyone have one? Pros? Cons?

    Couple specific questions:

    • I know they require a lot of juice. I have plenty of room between my two 100A breaker panels. Anything else electrically I need to consider? Also, will I realistically be looking at any savings over the electric tank?
    • I currently have two electric tanks hooked up in circuit with each other. The first is for reclaimed (preheated) water from the geo but has never been turned on. AFAIK I could simply swap out the tank that has been used and run the preheated water to the tankless heater. Or am I missing something?
    • How do these handle hard well water? We have the best of all worlds with really high dissolved mineral content, salt, and iron bacteria. We soften the crap out of our water but it’s still pretty hard by most standards.

    I’ve probably still got a couple years before it goes but the way we’re using hot water lately has me thinking it might be nicer to go tankless and not have to worry that my daughter just took a 20 minute shower with the dishwasher running and then getting a bath going for my youngest.






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    Last edited: Oct 19, 2020
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  2. Scadsobees

    Scadsobees

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    I can't comment on the electric or the really hard water.

    I'm going on 2 years with my gas heater, and love it. But I've got good water.

    They recommend running vinegar through it for a few hours every year to keep the buildup out of it. It's a fairly easy procedure that takes around 3 hours.

    I would imagine that the water would eat your pre-heater tank before it would eat up anything in the on-demand heater.
     
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  3. Scadsobees

    Scadsobees

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    Oh...as for as cost of running it... theoretically it's cheaper, but we do use a lot more hot water, since we can now shower all day without running out of water, if we wanted to. So it could end up costing more :).
     
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  4. M.Schmitz87

    M.Schmitz87 Premium Member

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    Ahw man. I can't help you with electric. If you are thinking about going with a gas tankless, let me know. I do about two of those per week and am a certified Navien tech.
     
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  5. M.Schmitz87

    M.Schmitz87 Premium Member

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    We found out that as soon as vinegar comes in contact with the scaled heat exchanger it looses it's effectiveness.
    I started using ice machine cleaner and have way better success with that.
     
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  6. d_rek

    d_rek

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    I should also add it needs to be an electric tankless heater. We don’t have gas coming into the house; house is 100% electric.


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  7. kroppe

    kroppe

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    Read up on what water quality/softness is needed as the input for the tankless heater. It strikes me as a large scale electric kettle (coffee/tea) and scale can be problematic, depending on water softness. What kind of filtration and softening do you presently use?
     
  8. Scadsobees

    Scadsobees

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    Do tell...how do you use the the icemaker cleaner? Do you need to run it as long as the vinegar?

    D_rek, I think the scale would be manageable, but you may need to do a flush multiple times a year to maintain it if your water is bad.
     
  9. jjlrrw

    jjlrrw

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    We have very hard water we still get yellowing after the softener, been using one over 10 years no problems, I would recommend plumbing it in with clean out valves so flushing would be very easy (we don't have these) and have neglected in the annual flushing but so far it's been okay.

    Also there is a learning curve if your shower is a single mixing valve, I have changed out to dual valves and just turn the hot on 100% and adjust the cold for temperature. 8 o'clock on the cold works for me, my wife like 9 o'clock.

    I don't think I would every go back to a tank heater too many advantages to a tankless IMO
     
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  10. d_rek

    d_rek

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    Currently we just only a large capacity salt softener system. I think it’s rated for 1000gal before a regeneration is required. Otherwise no additional filtration. I was told the softener is good enough to capture most of the dissolved mineral content but will not floculate the iron bacteria nor remove the dissolved salt. I think our hardiness is around 10gpg even after softening.


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  11. M.Schmitz87

    M.Schmitz87 Premium Member

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    I have a special pump system that i use only for water heater tune ups.
    Like I mentioned earlier I'm a navien certified tech but also work on other brands.
    A complete flush takes about 30 to 40 min. I used to flush with vinegar as well until I flushed a heater with vinegar first and with ice machine cleaner after. The amount of crud I got out of the second flush sold me.
     
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  12. koditten

    koditten

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    I think I'm better than most about taking care of my home maintanance. I don't think I could count on myself doing a yearly scale removal session.

    If I had hard water, I'd want nothing to do with on demand units.

    Pass.
     
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  13. Scadsobees

    Scadsobees

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    Lol, it's easy... turn the unit off, turn the water off, open the drain units, hook up the pump and tubes to the drains, fill the bucket with vinegar (or perhaps ice maker cleaner) and let it run for a few hours. Reverse steps when done.

    Very much worth the work for what I get. I'd gladly do it 2 or 3 times a year if I needed to rather than go back to a tank.
     
  14. M.Schmitz87

    M.Schmitz87 Premium Member

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    That's where maintenance plans come in handy. For a small monthly fee you can add years and years of life to your water heater and have a trained professional give you a complete tune up. Also you don't have to think about doing it, the shop will most likely give you a heads up when it's time for your annual maintenance.
     
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  15. Old Whaler

    Old Whaler

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    When I looked into one for my house, I was told by the owner of the HVAC company who did my furnace/AC that Bradford White has an excellent built in flush system. Said it's the only one he'll use. Might be worth a look.