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Tankless gas water heater or something like a Eternal water heater

bob eckbob eck Member Posts: 565
I know this is a heating question forum but I am wondering if you the professional heating and plumbing contractor are installing tankless gas water heaters or do you prefer a unit like the Eternal water heater? If installing tankless gas water heaters what brand are you using and why?


  • Aaron_in_MaineAaron_in_Maine Member Posts: 313

    I have not seen the eternal units yet. I have been installing Rinnai continuum water heaters for 7+ years. I have had one in my house for 3 years and love it.
    Aaron Hamilton Heating
    [email protected]
  • heatpro02920heatpro02920 Member Posts: 991

    I started installing Rinnai almost a decade ago and they are really nice units, I have them in most all my properties including my new 4 full bath 4000+sq ft home...

    I have been installing the newer condensing RU80i and RU98i units and really like them thus far, the older r53 units were solid and work great and the newer RL units are even better.... Most customers go with the rl75i due to cost, the RU98i adds around $900 to the install.

    I can run 4 showers and do laundry all at the same time and not run my unit down {ru98i}.

    I prefer them over indirects {even when a mod con is present}, conventionals, hybrids, ect...

    I tried Bosch, takagi, and a couple others before I tried the Rinnai and all of them had problems back then, the Rinnai has been a solid performing unit and a good money maker...
  • bob eckbob eck Member Posts: 565

    do you experience the so called cold water sandwich? Have you had to flush it out often?
  • heatpro02920heatpro02920 Member Posts: 991
    edited March 2013
    you have to weigh the pos and neg

    The water sandwich is not as noticeable as you would think and I have well water I flush the unit once a year {I have one almost 10 years old on city water never flushed it once, still works never a hiccup and its in a rental property, if they were having problems I would have 3 phone calls before noon}.. But you buy a $30 pump, a 5 ga bucket, a gallon of vinegar and a pair of washer hoses, it takes 20 minutes a year...

    When you turn the hot water on and off you will get a couple seconds of cold water in between the hot, but if the pipes are already warm from running the water with hot water in front of it and behind it you hardly notice the sandwich effect....

    I find different piping scenarios make this worse or better, with an insulated 1" pex main and home runs to all fixtures {sized correctly from 3/8 to 3/4} you wont notice it, with 1/2 uninsulated copper that runs all over a cold basement, it is more noticeable for some reason...

    If it bothers you, you can always install a pump, but that is hardy worth the trouble...

    With 3 people taking a 20 minute shower each, each day and then 1 load of laundry a day,1 load of dishes, and say another 20 minutes of on and off for hand washing and pot filling, you will run the unit 2 hours a day at a fraction of its firing rate, this gets you low energy costs and low wear and tear.... A lot better than keeping 40 gallons hot all day and night...

    I also like to install Highsierra shower nozzles at the same time as the Rinnai install... This adds to the savings and comfort... for a small cost...

    one more note with the newer units you get a smart pump control, so you can install a small circulator {ss 009 works well} and the unit will circulate hot water every so often, but this is kind of a waste of energy...
  • RobGRobG Member Posts: 1,850
    My pet peeve

    What bothers me about the tankless units is getting my wife to understand that when doing anything quickly, like rinsing her her hands after cutting vegetables, do not just flip up the single lever faucet in the middle (warm water position). It will cause the unit to fire although hot water will never get to the fixture by the time she's done. I'm tempted to replace my single lever faucets for two handled to stop this. Once again, you have to teach people a new mentality of hot water. But in my wife's case, you can't teach an old horse new tricks. 

  • heatpro02920heatpro02920 Member Posts: 991
    non mixing

    type faucets are the best bet with a tankless for sure, but there seems to be less and less of them getting installed..
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