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  1. #1
    Join Date
    Apr 2006
    Posts
    4

    Question

    After getting three bids, I decided to go with a contractor that offers the package (A/C, Furnace and EAC)that I like (American Standard) at a fair price. I called him and asked about doing a load calc to make sure it's sized correctly. He reiterated that he didn't really think it would be off from his estimate and load calcs are off sometimes too, but if it would make me feel more confident, he could get a guy out there to do some measurements. He then called back and said that the guy couldn't get out for a few days and it would speed things up if I did some measurements and gave some information on windows, insulations, etc., sketched out my house and faxed it in so they could run it through their program. (the need for speed is that our AC is out and it's getting warm here in St. Louis)

    So my confidence in them is shaken some now. Everything I've read here strongly recommends switching contractors if they balk at doing a load calc. We've used them for service in the past and had been very satisfied with their thoroughness, communication, and work.

    I should say that we have a standard looking starter home, 1140 sq. ft. ranch style with finished basement that is very common and may be among the easier to eyeball or trust that the size is similar to the previous units.

    My question is, should I lose faith in this contractor?

  2. #2
    Join Date
    Jan 2005
    Location
    Crooksville, Ohio
    Posts
    77
    Speaking for myself, I do my own heat load calcs. I would not depend on someone else giving me measurements if my companys name was on the contract. From what you have said, it sounds to me that this contractor really doesn't want to do a load calc, but wants to install quickly. That alone would raise a red flag to me.
    All Seasons Heating & Cooling

  3. #3
    Yes would think about it you will be living with this system for 10 to 20 years and you want to eyeball or trust that the size is similar to the previous units.


  4. #4
    Join Date
    Aug 2002
    Location
    Southold.calm
    Posts
    5,739
    Click on the Red Tab above and do your own. Worth the $50. Let this contractor know you want one done by him before any work will be started. If he has a problem with that then get someone else.

  5. #5
    Join Date
    May 2000
    Location
    Indianapolis, IN, USA
    Posts
    34,234
    Co-worker went on a sales call. Jerk was getting 6 frigging bids all in 1 day. Had to push next guy back since Scott was so thorough. Only one out of the 1st 4 to do measure and calc. Can't base on the outdoor unit, tag was worn off so the guessers really have to guess on this one. Hope his doing a proper job helps us get the job but most that call 1/2 the phone book are only out for a low bid.

  6. #6
    Join Date
    Sep 2002
    Location
    South Dakota
    Posts
    6,579


    No you should not have to do your own load calculation! However, reality is that by my opinion less than 10% of all HVAC contractors have the ability or knowledge required to perform such a calculation!

    Few contractors have even the basic of load calculations under their belt.

    It will be difficult for you to find a contractor who follows what should be the standard of the industry. Performing a load calculation on every job.

  7. #7
    Join Date
    Apr 2004
    Location
    Bartlett, IL
    Posts
    6,619
    I know how to do heat load calculations, but mainly do them when I design the system myself, (new construction) on replacements, I would ONLY do them if it was a tricky house with many rooms, windows, etc. Otherwise a house is a house, if I've installed the proper size equipment on one house and the footprint is pretty much identical to the ones I've just done...then I don't bother with a heat load.

    Many homes have undersized ductwork to begin with, unless you feel like shelling out some big bucks to rip down drywall, install properly sized ductwork and re-rock your walls, then you may get a "proper" system, otherwise you just can't get that "perfect" system because we don't live in a perfect world...heatload calc or not.

    IMO

  8. #8
    Join Date
    Apr 2004
    Location
    Bartlett, IL
    Posts
    6,619
    Originally posted by NormChris


    However, reality is that by my opinion less than 10% of all HVAC contractors have the ability or knowledge required to perform such a calculation!

    Few contractors have even the basic of load calculations under their belt.

    "Reality is by your opinion"? What the hell does that mean?
    Sounds like an oxymoron to me if I'd ever heard one.

    Less than 10%? where do you live, in a small city located in Rhode Island?

  9. #9
    Join Date
    May 2004
    Location
    Rapid City, SD
    Posts
    7,415
    FWIW, I never see load calcs done here unless it's a really weird house or commercial.

    You shouldn't have to, but it's a small price to pay for comfort for many years to come.
    "If you call that hard work, a koala’s life would look heroic."

  10. #10
    Join Date
    Mar 2002
    Location
    Concord, CA
    Posts
    2,635
    Originally posted by 2hot2coolme
    Originally posted by NormChris
    However... less than 10% of all HVAC contractors have the ability or knowledge required to perform such a calculation!
    Less than 10%? where do you live, in a small city located in Rhode Island?
    Your interest in proper grammar aside, it sounds like he lives in the real world to me.

  11. #11
    Join Date
    Feb 2004
    Location
    5280
    Posts
    466
    It does not take much time to do a proper heat load, so why not do it?

    We heat load almost very job (no need on a 600sq ft condo). Most homes around here have over sized equipment. 90% of the time we install (after heat load) smaller equipment than our competitors had bid. Rules of thumb, lead to over sizing equipment. Over sizing leads to higher energy usage and higher cost to the customer. No contractor wants a call saying the equipment that they installed can’t keep up with the demand. So installing a larger unit is the answer. If the actual load is known there is no need to upsize equipment.

    Properly sized equipment provides a more comfortable home at a lower energy cost to the home owner. A little time spent by the contractor to perform a proper load calc is not too much to ask for, it should be expected.

  12. #12
    Join Date
    Feb 2004
    Location
    Tucson AZ
    Posts
    55

    Insist on a load calculation

    I have done countless load calculations and the one thing I have learned is I could not possibly eyeball the size unit for a home without over-sizing the equipment. I constantly put in smaller units than my competitions. I would select a company that offers to do a load calculation not one being forced to. It is easy to manipulate the results. The companies that do this on a regular basis will be comfortable to accurately enter the information and believe the results. It took me a while to believe I could install what my calculations said even though my competition was recommending ½ to in some cases 2-tons larger than me for a single system home.
    BTW home owners that believe “bigger is better” make it not worth doing load calc’s for contractors. They don’t want to put in the time and effort to hear that flyby HVAC is offering a larger unit for less $$$$ even though they were able to evaluate the home in 10 minutes. I have begun to do my initial bids without doing load calculations for price comparison and will do a load calc prior to installation. I also offer a 100% satisfaction guarantee. If the unit wont keep the home cooled I will replace it at no cost. Over the last 6 years I have not had to replace a single system.

  13. #13
    Join Date
    Apr 2006
    Posts
    4
    Thanks everyone for your replies. So it seems that I can either go with my current contractor and cross my fingers that it would be sized about right while risking it being oversized, less energy efficient, and possibly have a shorter life,

    OR keep searching for a contractor that OFFERS to do a load calc to have more confidence in it being properly sized.

    Obviously, the ideal would be a load calc done but with already pursuing three bids and none of them even mentioning a load calc, I'm guessing the reality of finding someone that thorough is difficult, especially since with no AC currently, time of of the essence.

    Thanks for your thoughts, I may have to go with doing my own load calc.

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