Heat loss with plastic pipe?

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by Grayfeathers, Jul 29, 2008.

  1. Grayfeathers

    Grayfeathers New Member

    Messages:
    27
    Location:
    Pleasant Grove, Alabama
    Question. Buying a new home, brand new. I noticed that the house is plumbed completly with plastic pipe. Not sure what brand or thickness. I've also noticed that in my area, Brimingham, that most new construction is going with this plastic pipe. My question is this. When I plumb a water heater in I always insulate the copper on the hot side, to keep the heat loss at a minimum. When I went to inspect the house the other day I noticed that the line coming out of the hot side was extreamly warm, too hot to keep your hand on it for any time. Should I be concerned with heat loss or am I just making someting out of nothing.
  2. jimbo

    jimbo Plumber

    Messages:
    8,997
    Location:
    San Diego
    First, plastic pipe should not be connected directly to the water heater. There should be metal ( copper ) for the first 18". This is especially important on a gas WH due to the proximity of the flue.

    Plastic does not conduct heat like copper, but it does conduct and lose heat, so should be insulated.
  3. Grayfeathers

    Grayfeathers New Member

    Messages:
    27
    Location:
    Pleasant Grove, Alabama
    The water heater in question is an electric and not a gas. Whether or not that has any bearing on it or not, to me it should be insulated regardless of type of water heater.
  4. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,032
    Location:
    Cave Creek, Arizona
    pipe

    It SHOULD be, but seldom is, unless the builder specified it and wished to pay extra for it which few do. Heat rises so the pipes on the top of the water heater WILL be hot, but only to the point where the pipes turn downward. If it is in a basement, or the piping is overhead, it is possible for the heat to gravitate for a considerable distance from the water heater. If the piping is below the water heater the convection will stop as soon as the piping turns downward.
  5. Redwood

    Redwood Master Plumber

    Messages:
    7,450
    Location:
    Connecticut
    Welcome back Grayfeathers,
    Under most codes I know of there should be 18" of metal pipe before the plastic tubing connects. You may want to check on this with the local inspector.

    Did your hammering fix make it past the inpection?
  6. Grayfeathers

    Grayfeathers New Member

    Messages:
    27
    Location:
    Pleasant Grove, Alabama
    Inspection passed

    The purchasers love the house and looking forward to moving in.

    I'll have to check the local code for the 18" of metal pipe. I know that this has a brass fitting that's about 3/4 to an inch tall then the plastic pipe begins. Like I said earlier, most contractors in my area are getting away from running copper, cheaper I guess. I may spend the extra money over time and insulate the hot side of the system but not sure if the savings will off set the cost of the insulation.
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