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  1. #1
    Join Date
    Jan 2007
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    115

    HVAC Calc - Window Work Around, cement, ec..)

    I'm considering re-buying HVAC-Calc ( I bought it some time ago w/the 2 month version as I built my house). This time to consider insulation and ac/h tightening implications to load. But, it's not really oriented for some of these things. So, a few questions:

    1) Any idea how I tell it what r value window shade I'm considering. So much heat flows through a window I'd think this would matter, but it barely acknowledges shades and give no "R" rating. Any idea's how to vary r value's of blinds?

    2) What does one use for a poured foundation? It's neither block (airgap) nor ICF...

    3) Does it account for fiberglass reduced performance as temp drops? I know it give us R ratings, but fiberglass losses "R" performance as it cools rather significantly...

  2. #2
    Join Date
    Feb 2003
    Location
    Huntsville,AL
    Posts
    4,125
    Item 3= Wrong
    harvest rainwater,make SHADE,R75/50/30= roof/wall/floor, use HVAC mastic,caulk all wall seams!

  3. #3
    Join Date
    Nov 2004
    Location
    SW FL
    Posts
    6,295

    Thumbs up

    Quote Originally Posted by danf58 View Post
    So, a few questions:

    1) Any idea how I tell it what r value window shade I'm considering. So much heat flows through a window I'd think this would matter, but it barely acknowledges shades and give no "R" rating. Any idea's how to vary r value's of blinds?

    2) What does one use for a poured foundation? It's neither block (airgap) nor ICF... ..
    U= 1/R

    1) U-value of single pane = ~ 1.2
    U-value of double pane = 0.3 - 0.8

    Get the SHGC (tinting) correct for Your window
    Clear 0.7
    Light Tint 0.5
    HIgh Performance 0.3

    Look at PPG website for many windows.

    http://corporateportal.ppg.com/NA/Id...ssOverview.htm

    Blinds about 20% less.
    IE Clear 0.7 without 0.57 with blinds.
    Obviously, a large variation.

    2) perhaps R-1 or R-2
    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

  4. #4
    Join Date
    Jan 2007
    Posts
    115
    CEM-BSEE:

    You would be one of the few to think that. But I appreciate the thought anyway.

    Dan sw:

    I hate to be dense, but I don't see how that tells me the ratings for the existing shade options in HVAC-Calc or a way to add R value for shades to it. Can you clarify?

  5. #5
    Join Date
    Nov 2004
    Location
    SW FL
    Posts
    6,295

    Cool

    Quote Originally Posted by danf58 View Post
    ..., I don't see how that tells me the ratings for the existing shade options in HVAC-Calc or a way to add R value for shades to it. Can you clarify?
    Do you know if your windows are tinted? Double pane?

    SHGC for blinds would be about 20% less windows.
    IE Clear SHGC = 0.70 without blinds
    _______SHGC = 0.57 with blinds.

    Input in HVAC-Calc is up to you. I use Wrightsoft RSR

    SHGC = Solar Heat Gain Coefficient = .875 * SC
    __SC = Shading Coefficient


    ________

    # 3
    ... but fiberglass losses "R" performance as it {cools < NOT } absorbs moisture rather significantly...
    # 3
    Last edited by dan sw fl; 02-27-2007 at 08:28 PM.
    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

  6. #6
    Join Date
    Jan 2007
    Posts
    115
    Ah, not a HVAC-calc user. That explains it. But anyway, double pane.

    See, in hvac calc ( the issue at hand) there appears to be no way to enter in the parameters you mention. A simple interface (I assume that's why it's liked). But support is very limited. Don expects the user community to answer most questions....

    #3. I didn't follow again. Cryptic mood tonight maybe? anyway, yes, we'd agree it absorbs moisture too, and that is bad as well for it's performance....

  7. #7
    Join Date
    Nov 2004
    Location
    SW FL
    Posts
    6,295

    Hmm

    Quote Originally Posted by danf58 View Post
    Ah, not a HVAC-calc user. That explains it. But anyway, double pane.

    See, in hvac calc ( the issue at hand) there appears to be no way to enter in the parameters you mention.
    Double pane, low E and shaded are easily input in Room / Wall / Windows
    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

  8. #8
    Join Date
    Jan 2007
    Posts
    115
    Yes, they are. Maybe I wasn't clear. How is the "R" value of the shade set, what is assumed "R" value of the shades that exist, or what is some other way of assigning a "R" value to the shades?

  9. #9
    Join Date
    Nov 2004
    Location
    SW FL
    Posts
    6,295

    Smile

    Quote Originally Posted by danf58 View Post
    Yes, they are. Maybe I wasn't clear. How is the "R" value of the shade set, what is assumed "R" value of the shades that exist, or what is some other way of assigning a "R" value to the shades?
    Check
    ASHRAE Fundamentals
    or

    Chapter 6 Windows & Doors at

    http://southface.org/web/resources&s...ders_Guide.pdf
    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

  10. #10
    Join Date
    Jan 2007
    Posts
    115
    OK. Thanks dan.

    Anybody else care to comment on how I might be able (WITHIN HVAC-CALC) to assign different "R" values to different window shade treatments?

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