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Heat Loss

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James Day_2
James Day_2 Member Posts: 191
I'm doing a heatloss on an old brick commercial building.  Heat Loss is for 3rd Floor only.  Around 3500 sqft, 2ft thick brick construction.  What would be a good air exchange number to use for infiltration factor.  I am using Uponors heatloss program and not sure what number I should use for that old of a commercial building.  Ceiling is R-19 insulation.  I usually use wrightsoft but am trying out uponors heatloss.

Thanks, James

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  • Jamie Hall
    Jamie Hall Member Posts: 23,650
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    That's one of those questions...

    Are there windows?  What kind?  How big?  How new?  Are doors?  Etc. etc. and so on...



    In a previous incarnation I did a fair amount of work on building inspection, and we were always fussing about not enough air changes per hour -- a matter of indoor air quality.  But it depended a lot on the usage of the building.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • James Day_2
    James Day_2 Member Posts: 191
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    Heatloss

    All single pane windows. R-19 ceiling. Heated apartment below. Not a tremendous amount if windows. No doors to outside.
  • CMadatMe
    CMadatMe Member Posts: 3,086
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    Factor

    use a value of 1.25

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  • James Day_2
    James Day_2 Member Posts: 191
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    Heatloss

    thanks chris
  • TonyS
    TonyS Member Posts: 849
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    Plug in a few different numbers

    High Med Low and see if its enough of a difference to take you to the next size boiler,if not don't worry about it.. I am not familiar with that program, I use HVAC Calc and it is a simple matter to go back and change any parameter. I just finished a heat load on a home, came out 73000. So on the TT line that put me at a 110 no matter where I set the infiltration. If it would have been 108000 with med infiltration I would have had to make a call.
  • Mark Eatherton
    Mark Eatherton Member Posts: 5,853
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    The OLD code called for 1.5 NACH...

    One way to confirm it for sure would be to do a commercial blower door test. Why guess? For less than $300 you will KNOW where the air is coming from, and how much, and might be able to cut back on some of it to save energy.



    ME

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