KISSIMMEE, FL — The Air Conditioning Contractors of America (ACCA) held a press conference at its 34th Annual Conference to provide a “sneak preview” briefing on Version 8 of Manual J, the industry standard for residential load calculation.

Manual J contains calculations for heat gain and heat loss for residential structures. The new version is its first major revision in 15 years. The updated Version 8 was a collaborative effort spearheaded by Hank Rutkowski, ACCA technical consultant, and Glenn Friedman, a technical consultant for Taylor Engineering, Alameda, CA.

“Given changes in efficiencies and construction, we needed a new process for load calculations,” said Friedman. “Manual J is the flagship of [ACCA’s] manuals and it has lacked the ‘sensitivity’ to keep up with modern technologies.”

Rutkowski has high praise for Version 8. “We have a product which has no competition from anything else in the world,” he said. “Manufacturers of sophisticated products ask us to put their product information into Manual J. In general, they support Manual J because they don’t want to see their equipment coming back because of failures [due to poor installations].

“The last thing that contractors needed was a more complex system of calculations. We had to tell contractors to wait for separate calculations, which weren’t available in Version 7.”


Friedman highlighted some of the new features at the trade media press conference. They include:

  • Peak load procedure involving energy usage at all times of the day, all year long.
  • NFRC glass added to calculations of “actual” heat loss via windows and includes window screens in calculations.
  • Dust load factor tables addressing the methodology of measuring dust loads.
  • Cfm requirements now include updated IAQ information.
  • Multiple-zone system calculations.
  • Version 8 will be available in CD format.

    “The revised Manual J is a business opportunity for contractors,” said Jim Hussey, ACCA 2002-2003 chairman. “It differentiates our contractors from others — it deals with correct load sizing.

    “Contractors have been drawn into the IAQ business and it is up to them to explain the benefits of a better-sized system.”

    Paul Stalknecht, president and ceo of ACCA, said Version 8 is just what contractors have been waiting for, and continues to be the “cornerstone of ACCA’s technical library.”

    “Everybody kept telling us to get Manual J out on the street,” he said. “We are challenged to get this information out to consumers, too. We want to make sure all of our manuals are ahead of the curve.”

    Version 8 of Manual J will soon be available. For more information or to order, visit (website).

    Publication date: 03/18/2002