Exterior vs interior wall cavities for water supply - just curious

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by bmusgrove, Sep 25, 2014.

  1. bmusgrove

    bmusgrove New Member

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    Cedar Hill, Texas
    This is just a post out of curiosity. Please note that when I say Right or Left in this, I am referring to right or left while looking at the front of the house.


    I have a 2 story house. The 2nd floor has a master bath and Full guest bath. Bath room arrangement is Left Side of the House - master bath - Master Closet - guest Bath - Hallway - bedrooms - right side of the house. All of these back onto a walk in half attic.

    The hot water heater sits in a garage closet directly beneath the Master Closet. Now my questions: Hot water is routed from the heater, into a interior wall down into the slab. From there it splits. For the guest bath it moves to the right 10 feet, goes up a interior wall cavity into the half attic for 3 feet and into the Guest bathroom. The master bath is routed into the slab, 25 feet to the left, up a EXTERIOR wall and then into the half attic and then into the master bath.

    What is the design philosophy behind using a exterior wall? To this amateur it would make more sense to duplicate the guest bath setup. Run it up a interior wall to the attic go left 3 feet and into the master bath. In fact it could go up the same interior wall as the 1st floor clothes washer which is directly beneath the master bath,

    I am in Dallas Texas. Freezing colds temperatures occur maybe 14 intermittent days a year.
     
  2. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

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    Habit is probably the main reason why they ran it that way...doesn't make it right or the best or even wrong. If the pipe in an exterior or attic space is on the house side of the insulation, unless there is an air leak (that's a BIG IF!), it probably doesn't matter much. The bigger hassle is that it runs through the slab anywhere...when, (not if) it leaks, you'll be rerouting the pipes and you can run them where ever you choose! And, while it is not uncommon to have the WH in a garage, I prefer not to have it in unconditioned space. It's a harder decision when you don't have a basement, though, and in a predominately cooling environment, putting a heat source out of the conditioned space makes some sense. Not as much if it is electric verses gas, though.
     
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  4. bmusgrove

    bmusgrove New Member

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    The pipes run up a non insulated exterior garage wall. Another head scratcher. The WH could easily have been inside or outside. Remove the closet door , wall it up and cut a door in side the house. I wonder if it's facing into the garage because it's designed take electric or gas... Doesn't matter. That's beyond the scope of my question and curiosity.
     
  5. Tom Sawyer

    Tom Sawyer In the Trades

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    Why do you need a hot water heater? Is there a reason for heating hot water?
     
  6. hj

    hj Master Plumber

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    quote; Why do you need a hot water heater? Is there a reason for heating hot water?

    Yes, because it is NOT HOT ENOUGH. The way the piping is arranged does NOT have to be logical to you, as long as it was to the installer.
     
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  7. Tom Sawyer

    Tom Sawyer In the Trades

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    So you need two. One to heat the water and the other to heat the hot water? Lol
     
  8. Reach4

    Reach4 Well-Known Member

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    I know somebody with a gas water heater in series with an on-demand electric water heater.
     
  9. bluebinky

    bluebinky Member

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    Only in Maine. In Arizona, the water is hot to begin with, but not hot enough for doing dishes and such ;)
     
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  10. bmusgrove

    bmusgrove New Member

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    By any chance are your bubblehead? That's exactly what I would expect from a fellow bubblehead! :)
     
  11. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

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    Retired Systems engineer for defense industry.
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    New England
    Being practical, it's a cold water heater. Saying hot water heater is kind of silly once you think about it.
     
  12. Tom Sawyer

    Tom Sawyer In the Trades

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    Just yanking your chain.
     
  13. hj

    hj Master Plumber

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    quote; So you need two. One to heat the water and the other to heat the hot water? Lol

    No! First the heater heats the "cold" water, (cold water heater), but it almost immediately becomes warm water so the heater becomes a "warm water heater" until the water gets hot. If you need it hotter, then the "hot water heater" takes over and make the water even hotter.,
     
  14. bluebinky

    bluebinky Member

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    Whatever you cal them, the new thing here in California is the government is trying to ban the use of DHMO in our "... heaters". For more info on the dangers of DHMO, see http://www.dhmo.org/facts.html.
     
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