Water heater on uninsulated slab

Discussion in 'Water Heater Forum, Tanks' started by Lightwave, Jan 16, 2010.

  1. Lightwave

    Lightwave New Member

    Messages:
    98
    Location:
    Vancouver, BC
    What are the energy use implications of installing an electric water heater on an uninsulated slab on grade basement floor?

    Is it worth building an insulated platform to keep the tank off the floor or are typical water heaters insulated well enough for conduction losses through the floor to be a non-issue?
  2. Redwood

    Redwood Master Plumber

    Messages:
    7,450
    Location:
    Connecticut
    There is very little heat loss through the bottom or, anywhere else for that matter on a new foam insulated electric water heater.

    Although some here would propose that you spend 50 bucks to save a nickel.:rolleyes:

    Look out here they come!:eek:
  3. Lightwave

    Lightwave New Member

    Messages:
    98
    Location:
    Vancouver, BC
    It's a 12 year old John Wood tank. Dunno if that counts as 'new' or not.
  4. Redwood

    Redwood Master Plumber

    Messages:
    7,450
    Location:
    Connecticut
    Leave well enough alone and don't touch a thing.
    You'll probably replace it soon enough.
  5. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,817
    Location:
    Cave Creek, Arizona
    heater

    Any money you spend doing it will be wasted. And do NOT do it with an "old" heater which yours is.
  6. john wood???

    John Wood??? never heard of that brand.....

    where did it come from anyway

    ace hardware??
  7. Redwood

    Redwood Master Plumber

    Messages:
    7,450
    Location:
    Connecticut
    I've seen a few around here Mark, a couple of places sell them.
    Real popular brand in Canada where the OP is located.
  8. Runs with bison

    Runs with bison Member

    Messages:
    892
    Location:
    Midwest
    There was a recent discussion of this topic. Contrary to Redwood's assertions (he's not shown any aptitude at econ or heat loss calcs), there has been no call to use them here, but according to Terry and others they are required by code in some areas. http://www.terrylove.com/forums/showthread.php?33770-foam-block-under-water-heater

    As to how long your tank will last, depends on the water, usage, and unknown factors in the production of the tank itself. Beware the BW shilling...for some the answer to every question seems to be to replace it with a BW water heater regardless of age or expense.
  9. nukeman

    nukeman Nuclear Engineer

    Messages:
    711
    Location:
    VA
    I would insulate the pipes, if they are not already, and call it a day. Conduction losses through the bottom of the tank would be way down on the list. When you do replace the tank, that would be an easier time to do the platform if you still wanted to do it at that time.
  10. Redwood

    Redwood Master Plumber

    Messages:
    7,450
    Location:
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    So I take it your advice would be go ahead disconnect a 12 year old water heater lift it up and insulate then reconnect...
    Keep on giving the bad advice and I'll have to put your famous quotes in my signature.
    You are getting to be just a little too much of a Bozo...
    Try sticking to what you know as little as that may be...

    Nuke Man's advice on insulating the pipes is always good advice.
  11. Runs with bison

    Runs with bison Member

    Messages:
    892
    Location:
    Midwest
    That was an idiotic post even for you. Once again you demonstrate a lack of basic reading comprehension. I said in the referenced thread that I saw no point to the insulation pad for electric. Your beef is with Terry I guess since he pointed out that they do reduce corrosion of the base next to the ground.

    Unlike you, I (and other engineers) can actually do the calcs to determine whether or not something make sense. Beats winging it with poor information as you are prone to do.

    Try sticking to what you know--which apparently ain't much. Right now it doesn't appear you could reason your way out of a paper bag.
  12. Runs with bison

    Runs with bison Member

    Messages:
    892
    Location:
    Midwest
    Gee, that would be what I've said...


    And that would be what you typically propose: replace a working water heater with a new one to fix a problem you've misdiagnosed. Spending ~$800 for what is most often a free repair is an even worse return than spending "50 bucks to save a nickel." With pipe insulation and insulating blankets on the typical R8 gas water heater the return is pretty good, about 50% annually on the jacket. (Loved how you completely misread that BW liability boilerplate, but as I've been pointing out: reading comprehension/judgement is not your strong suit.)

    Nice try on the strawman, but as usual you have it bass ackwards.
  13. Redwood

    Redwood Master Plumber

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    7,450
    Location:
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    Last edited: Jan 19, 2010
  14. Runs with bison

    Runs with bison Member

    Messages:
    892
    Location:
    Midwest
    Now Redwood is fogging himself, rather than flogging himself.
  15. Lightwave

    Lightwave New Member

    Messages:
    98
    Location:
    Vancouver, BC
    Thanks everybody for all the input.

    I'm not going to lift the current tank but when I redo the room and replace the tank, the new tank will be on an insulated floor rather than on the bare slab.

    The near tank piping is already insulated.
  16. Redwood

    Redwood Master Plumber

    Messages:
    7,450
    Location:
    Connecticut
    A Wise Choice!

    I would consider insulating all the hot pipes you have access to not just the pipes near the tank.
    There is more savings there than under the tank insulation.
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