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  1. #1
    Join Date
    Nov 2007
    Location
    Texas
    Posts
    425

    Do you guys really exist??

    I am in the process of convincing the company I work for the value of using load calculations and having software to assist in this process. I was discussing this with a tech today, and he began telling me this is all going to be a waste of time. "No one uses this stuff anymore, and I can tell you the cfm for a room just by looking." So..he got me wondering is it worth taking the time to learn to do proper load calculations? Does everyone here actually perform these calculations, or just feel they are important? He made the case that the time spent to perform a load calc. would not have good return was just not worth the time....

  2. #2
    Join Date
    Dec 2007
    Location
    Ohio
    Posts
    2,875
    Quote Originally Posted by hidalgo1301 View Post
    I am in the process of convincing the company I work for the value of using load calculations and having software to assist in this process. I was discussing this with a tech today, and he began telling me this is all going to be a waste of time. "No one uses this stuff anymore, and I can tell you the cfm for a room just by looking." So..he got me wondering is it worth taking the time to learn to do proper load calculations? Does everyone here actually perform these calculations, or just feel they are important? He made the case that the time spent to perform a load calc. would not have good return was just not worth the time....
    He's a fool.......

    I use them every time......
    I need a new signature.....

  3. #3
    Join Date
    Aug 2006
    Location
    Columbus Ohio
    Posts
    1,977
    If they don't bite on your "idea", you need to start looking for a new job.

    You can lead a horse to water.... You know the rest.
    UA LU189

    10mm, because it's better than .45acp

  4. #4
    Join Date
    Sep 2005
    Location
    Texas
    Posts
    2,793
    I can't say we use it on every single situation but yes we use it pretty faithfully....learn it, embrace it, enjoy it!

  5. #5
    Join Date
    May 2004
    Location
    Rapid City, SD
    Posts
    7,403
    If installs are what you do to make a living, you'd better be using it 99 times out of 100. There may be some cases where your gut might have a better idea than software for a certain room, but more often than not, it's what you should be doing.

    The only times I'd say you don't need to do a load calc is if you're doing a lot of spec houses (same) for the same builder, you can probably start using some rule of thumb that you learned from the 1st few you did and performed load calcs.
    "If you call that hard work, a koala’s life would look heroic."

    VETO PRO PAC, The Official Tool Bag of HVAC-Talk.com

    Testo... you guys rule!

  6. #6
    Join Date
    Apr 2007
    Posts
    6,285
    They don't report R and U values for no reason. Fenestration is not some random number thought up to sound cool. They're only a waste of time to people who want to sell the biggest system possible to make the most money they can, screw the end user who has to pay the bills. A load calculation doesn't have to be done every time, on something like a service call, but when the tech can no longer squeeze anything else out of the system and things still aren't right it's a very handy tool. When you do them enough times you'll understand the importance. You may understand the importance right away in the classroom...

  7. #7
    Join Date
    Sep 2005
    Location
    Texas
    Posts
    2,793
    I know for a fact that 9 out of 10 contractors around these parts don't even have load calculating software much less how to use it

  8. #8
    Join Date
    Nov 2007
    Location
    Texas
    Posts
    425
    Thanks for the quick responses. I tried to give him an example of the many homes that we go into where people are having windows replaced, insulation added, and radiant barrier put in place..and that a load calc. could help verify the proper size equipment rather than just replacing with the same tonnage. He just basically said he had "been there, done that" and that I would eventually realize that I didn't need to know this stuff. I agree with you guys, and I will just have to do my own thing.

  9. #9
    Join Date
    Apr 2007
    Posts
    6,285
    It is common for mechanical systems in residential construction to be oversized which increases installation costs, wastes energy, and reduces comfort and moisture control. Properly sized equipment will last longer, provide greater comfort, reduce noise, and save homeowners money. Yet both builders and code officials are uncertain how to evaluate such calculations to assure they meet the intent of the code plus the sizing methodology approved in Air Conditioning Contractors of America (ACCA) Manual J (or equivalent).

    The 2003 IECC requires sizing calculations to be performed on every home using the procedures described in the ASHAE Fundamentals Handbook - 2001. Chapter 14 of the 2003 IRC requires heating and cooling systems to be sized to ACCA Manual J - Seventh Addition or other approved heating and cooling load calculations. Both methods have sufficient built-in safety factors to accommodate most conditioning needs. Therefore, it is important to follow all instructions in ASHRAE Fundamentals or Manual J using precise area measurements and specific data.


    Heating and cooling loads can be determined using a whole house approach or performing a room-by-room load calculation. The room-by-room approach provides the information needed to determine the number of cubic feet per minute (cfm) needed of conditioned air to satisfy the heating and cooling load for the room. This information can then be use to determine the duct size necessary to deliver space heating and cooling for the space.
    http://resourcecenter.pnl.gov/cocoon...r/article/1468

  10. #10
    Join Date
    Dec 2002
    Location
    Arizona
    Posts
    4,233
    Quote Originally Posted by air2spare View Post
    I know for a fact that 9 out of 10 contractors around these parts don't even have load calculating software much less how to use it
    So if your one that does that puts you in the top 10%. Good place to start the sales process.
    Make your expertise uniquely valuable.

    Make your influence uniquely far-reaching.

  11. #11
    Join Date
    Nov 2007
    Location
    Texas
    Posts
    425
    Quote Originally Posted by air2spare View Post
    I know for a fact that 9 out of 10 contractors around these parts don't even have load calculating software much less how to use it
    Do you use it? Has it been beneficial to you? I ask just because I want the knowledge as well as to be able to be a benefit to the company that is willing to purchase this software.

  12. #12
    Join Date
    Feb 2005
    Location
    Barrie, Ontario
    Posts
    4,622
    If all you're doing is cookie-cutter structures, you may only need one calc adjusted for compass direction, but if you're doing any custom work...

    Yes, I have one. It's older, put out by a manufacturer 10 years ago, simple to use and I like it. It came on a 3.5" floppy and I transferred the program onto my external hard drive before I gave up the floppy drive and now can put it anywhere I need it. Even an older one is better than none.
    Is this a Fabreze moment? C.Y.D. I'm voting white elephant. 2’.
    My competition are my best salespeople!

  13. #13
    Join Date
    Nov 2007
    Location
    Texas
    Posts
    425
    We do residential replacement and remodels.

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