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What does this mean?

Zman
Zman Member Posts: 7,611
edited July 2019 in THE MAIN WALL
I am doing some light reading in the 2018 IECC https://codes.iccsafe.org/content/IECC2018P3/chapter-4-re-residential-energy-efficiency

Does anyone know what this part of Table 405.5.2(1) means?

I keep coming up with millions of Btu/day for a 1,000 square foot home. That can't be right...
"If you can't explain it simply, you don't understand it well enough"
Albert Einstein

Comments

  • STEVEusaPA
    STEVEusaPA Member Posts: 6,505
    1000 sq ft and 3 bedrooms = 54012
    =17900 + (23.8 x 1000) + (4104 x 3)
    =17900 + 23800 + 12312
    =54012

    There was an error rendering this rich post.

    Zman
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 16,470
    forgot what that's called .............order of...........something
  • Jamie Hall
    Jamie Hall Member Posts: 24,845
    I have to admit that the way it's presented isn't perfectly clear... @STEVEusaPA 's parentheses are correct -- but it would be better if the publisher had put them in in the beginning, because @Zman 's interpretation isn't actually incorrect, considering just the way it's written, either.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Zman
    Zman Member Posts: 7,611
    Thanks @STEVEusaPA
    I guess you need to go to the IMC before they will trust you with 8th grade algebra order of operations :D
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
    Solid_Fuel_Man
  • STEVEusaPA
    STEVEusaPA Member Posts: 6,505
    edited July 2019
    👍
    It’s actually correct the way it’s written. When no parenthesis are written, order of operations are the rule.
    Just think of a formula with no parenthesis like:

    π r^2
    You would square the radius before multiplying π.

    There was an error rendering this rich post.

    Zman
  • LuckyDog
    LuckyDog Member Posts: 22
    Hey, at least he knew enough to know something was wrong....

    Unlike some fresh-outta-school engineers I have met.
    :)

    There was an error rendering this rich post.

  • rick in Alaska
    rick in Alaska Member Posts: 1,466
    I came up with 54,600 for my house. Which works out to be 2,277 btu's per hour.Interestingly, the formula assumes all the bedrooms are occupied to get that reading. That would have to be something to factor in if you were trying to get a very accurate heat loss of the house.
    Rick
  • Zman
    Zman Member Posts: 7,611
    LuckyDog said:

    Hey, at least he knew enough to know something was wrong....

    Unlike some fresh-outta-school engineers I have met.
    :)

    I had an "AHA" moment as soon as @STEVEusaPA pointed it out. The class where I learned order of operations was more than a few years ago :)
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • STEVEusaPA
    STEVEusaPA Member Posts: 6,505
    I wonder how the kids solve that equation with the new style math?

    There was an error rendering this rich post.

  • ratio
    ratio Member Posts: 3,789
    "Siri whats the ansrwe"?

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