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Recommendations for Manual J software?

silkwj | Posted in Mechanicals on

Hi All,

I’m looking into software to perform Manual J calcs, and perhaps also do other simulation/calculations as well. I’m fluent with the PHPP and another software called TrnSys (from a previous job), but I’m looking for something more common in the residential efficiency world.

I’ve read Martin’s article about Manual D & J calcs and the software links there, but before I go and drop $300-500 on software that may or may not be decent, does anyone have any recommendations? I’m a mechanical engineer and fairly computer literate but still would appreciate a well thought out and easy to use software.


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  1. Expert Member
    ARMANDO COBO | | #1

    The two most common software used by HVAC folks are Elite and Wrightsoft.

  2. user-626934 | | #2


    I doubt you'll find one that's "well thought out and easy to use." The four Manual J software packages referenced in Martin's article are currently the only ones that are ACCA-approved. That said, I use Wrightsoft (Right-J) for Manual J work.

    Manual D calcs don't require special software. I use my own Excel spreadsheet using the methods and formulas in the manual because it makes more sense to me than the inputs in Right-D.

  3. GBA Editor
    Martin Holladay | | #3

    Perhaps it's worth reminding GBA readers that before computers became available, engineers and HVAC contractors (and 21-year-old college dropouts) routinely performed heat loss calculations with a pencil and paper.

    When I worked for Shepard Corporation, a wholesale plumbing and heating distributor in St. Johnsbury, Vermont, in the late 1970s, the company performed heat loss calculations as a service to its customers. Any contractor who bought a furnace or boiler from Shepard was entitled to a free heat loss calculation and heating system design. I did the work with a paper and pencil.

    I performed a room-by-room heat-loss calculation, using a pad of paper from I=B=R called the "I=B=R Calculation Sheet." (I=B=R is the Institute of Boiler and Radiator Manufacturers.) I had ASHRAE tables of U-factors and R-values of various building components, as well as a table to convert BTUH calculations at a delta-T of 70 degrees to BTUH calculations at other delta-Ts.

    Once I completed the room-by-room heat loss calculations, I could size the boiler and design the heating system. For hydonic systems, I calculated the number of feet of fin-tube baseboard required for each room; kitchens and bathrooms sometimes got a kickspace heater. I also had a cardboard calculator for figuring duct sizes for hot-air systems.

    I just pulled out my old heat-loss calculation sheets and performed a room-by-room heat loss calculation for my brother. It took less than an hour, and I'm rusty. (An HVAC contractor in Boston told my brother that he needs a 115,000 BTUH furnace. It turns out that his design heat loss is 39,200 BTUH.)

    For more information on the I=B=R method, see

  4. silkwj | | #4

    Thanks for the tips guys. Sounds like I can accomplish the same thing with Excel, at least for now. Might take a bit of time up front but will be useful later on, especially since I'll know exactly what's in there (and what's not).

  5. RBean | | #5

    Amen to the pencil and paper and a nod to Excel...those with the ASHRAE manuals and you can pretty much calculate anything related to HVAC.

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