Results 1 to 8 of 8
  1. #1
    Looking at putting a new roof on the house after 15 years. Looking at replacing the original asphalt shingles and considering a metal roof. Have seen studies comparing metal to shingles which indicate a possible effect on the heating and cooling requirements. What are your thoughts?

  2. #2
    Join Date
    Jul 2002
    Location
    Zelienople, Pa
    Posts
    2,965
    There will be an effect.

    Run a Manual J with asphalt shingles vs. metal roof and post your findings...

  3. #3
    Join Date
    Feb 2003
    Location
    Huntsville,AL
    Posts
    4,125
    depends upon:
    type of paint used
    color of paint used
    seperation between roof & sheating
    attic ventilation
    type of sheating
    amount of shading
    roof orientation with respect to north
    harvest rainwater,make SHADE,R75/50/30= roof/wall/floor, use HVAC mastic,caulk all wall seams!

  4. #4
    Join Date
    Feb 2004
    Location
    5280
    Posts
    466
    Manual J 8th addition

    Category 16CR-38
    "Under attic or knee wall, Vented with Radiant Barrier, Dark Asphalt Shingles or dark Metal, Tar and Gravel or Membrane, R-38 insulation"

    The contributing factors are vented or unvented, Radiant barrier or No Radiant barrier, Dark or light color, and R-value.

    If you are replacing a dark asphalt shingle with dark Metal, Manual J load calc will not change.

    Tile or concrete will change your load.

  5. #5
    Join Date
    Mar 2005
    Posts
    157
    No difference on type of roof, it's the insulation in the attic that will save money.

  6. #6
    Join Date
    Aug 2003
    Posts
    626
    Majormickey--I can assure you the type of roof makes a world of difference as to how much radiant heat, in summer, is transfered to the insulation below.

  7. #7
    The reason I asked was prompted by the following study:

    http://www.fsec.ucf.edu/bldg/baihp/c...roof/index.htm


  8. #8
    Join Date
    Nov 2004
    Location
    SW FL
    Posts
    6,234
    Originally posted by ylnesomdove
    The reason I asked was prompted by the following study:
    http://www.fsec.ucf.edu/bldg/baihp/c...roof/index.htm
    "Initial results for a nine week period in the summer of 2005 show the white metal roof providing a 19% savings in air conditioner energy over the same period in 2004"

    I believe that the 2005 temperatures in the subject area
    were > than in 2004.

    FSEC and a few other building sources provide
    VERY Reliable, well-documented studies.
    Designer Dan
    It's Not Rocket Science, But It is SCIENCE with "Some Art". ___ ___ K EEP I T S IMPLE & S INCERE

    Define the Building Envelope and Perform a Detailed Load Calc: It's ALL About Windows and Make-up Air Requirements. Know Your Equipment Capabilities

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