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Learning heat loss calcs - looking for infiltration factors

Macro
Macro Member Posts: 7
edited December 2020 in Radiant Heating
So I'm learning about heat loss calculations and boiler sizing etc. but I would like to be able to do that calculations myself manually before relying on a program or online calculator. I am finding it impossible to find the infiltration factor multipliers anywhere though. Can someone direct me to them? I don't mind if I have to pay for a download or book but I can't find it. I'm an ICI plumber but trying to expand my resi knowledge and skills to grow my own business. Thanks!

Comments

  • This is how we used to do heat loss calculations in the "old days":
    https://heatinghelp.com/assets/documents/110.pdf
    Thanks to Erin, Dan and HeatingHelp for keeping this in their archives.
    Often wrong, never in doubt.
    Erin Holohan Haskell
  • GW
    GW Member Posts: 4,304
    Infiltration, that’s the wild west, unless you have a blower door. This is a basic fundamental, the taller the structure, the more infiltration. The older the structure, the more infiltration. It’s likely why the old-timers put these huge radiators in the front entry/hallway.
    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    [email protected]
    MacroSteve Minnich
  • Macro
    Macro Member Posts: 7

    This is how we used to do heat loss calculations in the "old days":
    https://heatinghelp.com/assets/documents/110.pdf
    Thanks to Erin, Dan and HeatingHelp for keeping this in their archives.

    Thanks! There's a lot of old and roughly built homes where I am that I think this would be useful for. Is there any other resources you can suggest for learning about this stuff? I see reference to "Manual J" sometimes but I don't know what that is!
  • STEVEusaPA
    STEVEusaPA Member Posts: 5,313

    This is how we used to do heat loss calculations in the "old days":
    https://heatinghelp.com/assets/documents/110.pdf
    Thanks to Erin, Dan and HeatingHelp for keeping this in their archives.

    That one's too old, doesn't account for global warming. Neither does mine from the 80's.
    steve
  • Macro
    Macro Member Posts: 7

    Do you have a recommendation for where I can find something updated? Or even wheat to search for?
  • Jamie Hall
    Jamie Hall Member Posts: 17,080
    Macro said:


    Do you have a recommendation for where I can find something updated? Or even wheat to search for?

    I think at @STEVEusaPA was joking -- the basic concepts haven't changed a bit, global warming or no. The only thing really lacking -- and easily accounted for -- is better insulation in more recently built or upgraded structures.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 10,290
    @Macro

    Doing a few calculations manually is a good idea. Anyone can plug in a program and get results , but they won't know right from wrong.

    Doing a few manually will give you an understanding of how it works.

    Slant Finn has an app you can download that people use that is pretty good.
    Macro
  • Zman
    Zman Member Posts: 6,989
    Infiltration factor is always a bit of SWAG. The height of the building, location of the leaks, wind exposure and mechanical fans all play a factor.

    A blower door test eliminates many variables. comparing past utility bills to heating degree days is also a good trick.

    I like this article.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
    Alan (California Radiant) Forbesmattmia2
  • Macro
    Macro Member Posts: 7

    @Macro

    Doing a few calculations manually is a good idea. Anyone can plug in a program and get results , but they won't know right from wrong.

    Doing a few manually will give you an understanding of how it works.

    Slant Finn has an app you can download that people use that is pretty good.

    I was having a look through it and it seems pretty comprehensive, almost too much for me! I'm not familiar with all the different variables you can choose from (wall types mostly) so I need to dig into it a little more.
  • mattmia2
    mattmia2 Member Posts: 3,972
    Some of the inputs to the heat loss are always a best guess. The r-value of windows and wall and ceiling assemblies are also a best guess.
  • RNB716
    RNB716 Member Posts: 8
    I just went through this myself.... As a DIY project mind you. Without learning too much, lol, I found this to be of help.

    best of luck with your project.
  • Dave H_2
    Dave H_2 Member Posts: 478
    Take a look here, we went into detail on heatloss during the first few sessions of Taco After Dark, Summer School


    Dave H.
    Dave H
    Macro