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Manual J

Okay guys,

Which of you fine air conditioning contractors use Manual J to perform your residential heat gain calculations.

The feedback I have received in the past was that it took too long or it was too difficult to determine or obtain the structural details.

I am presently covering Manual J with my graduating class and they seem to like working with the tables and worksheets. Right now I have them doing all of the work by hand, so I know they are going to absolutely love it when they start using the spreadsheets tonight.

What's your take on Manual J?


  • don_169
    don_169 Member Posts: 1
    Thats a

    shame Professor.With today software its nothing to do one on the computer.
    Sure you have to go digging in the attic and crawl when doing a survey however,if the customer is told going in that its a cost to do so and their no such thing as a free estimate then you would properly see more contractor doing them.

    As for you making your student do them long hand then I say their no wonder they'll be throwing things at you.Just kidding.

    I still have my printed version and still refer back to it often..The software all tho is very easy it not loaded with
    lots of infro as the paper back.
    Also mine.. from 86 seventh edition.

  • Eugene Silberstein
    Eugene Silberstein Member Posts: 1,380

    The disc that accompanies Vesion 8 is a spreadsheet that will perform the calculations for you. You still need to the hard copy to look up the data on the tables.
  • Eugene Silberstein
    Eugene Silberstein Member Posts: 1,380

    You mean nobody is using Manual J? C'mon guys, there must be some brave soles out there...
  • Mark_7
    Mark_7 Member Posts: 123
    Manual J

    I use Wrightsoft for every job existing or new.That way we know what size the equipment should be and can check duct work at the same time would't do biz without it.Mark
  • CDM2
    CDM2 Member Posts: 18
    Manual J

    I started back in 1988 using Manual J and Manual N. The method of doing load clacs longhand proved to be very helpful once Bill Wright introduced Right-J. The company I worked for back then received a beat version in DOS. I have not looked back since that time.

    The manual is very informative, but the software speeds my process up tremendously. Like others who have posted here, I still refer to the manual from time- to time. And I think it should be part of the training process to learn to use the manual and long hand forms.

  • Constantin
    Constantin Member Posts: 3,796
    I used HVAC-Calc...

    ...my contractor used Wrightsoft and we came to within a couple of thousand BTUs of each other, so we're either both off or we did something right. Both programs used version 7, IIRC, of Manual J as a basis.

    Speed is an issue for some contractors, I guess. I found the data entry in HVAC-Calc reasonably quick and it also allowed me later to play with "what-if" scenarios, such as changing the insulation schedule, window-types, etc. which I found to be as useful as the actual result for the as-planned home.

    Talk about being able to make tradeoffs and matching the sensible/latent load to the equipment you're evaluating for purchase.
  • Tom_35
    Tom_35 Member Posts: 265

    I use Wrightsoft and we just got Elite because they interface with ECR direct exchange heat pumps. Both work very well.

    Tom Atchley
  • Eugene Silberstein
    Eugene Silberstein Member Posts: 1,380
    I've heard

    I've heard great things about Elite... Going to tap into my college budget to check it out!
This discussion has been closed.