ARLINGTON, Va. - According to the Air Conditioning Contractors of America (ACCA), a necessary first step in designing a quality residential HVAC system is conducting a proper Manual J® load calculation. Manual J is its national standard for calculating heat gain and heat loss. To aid in Manual J training, ACCA has released a new computer CD training package that is designed to take the complex concepts of Manual J, explain them in plain English, and offer real-world examples on how to apply them in day-to-day business using modern load calculation software.

“Understanding Manual J: Heat Gain & Heat Loss in the Real World” is the second in a new series of training materials being released by ACCA under the name “HVAC Essentials.” These recorded training sessions, which are viewed directly on a PC, allow people (individually or in groups) to learn these concepts at their own pace, in segments or all at once, depending on their own needs.

The first package in the series, “Understanding Manual D,” was released in September.

“Understanding Manual J” consists of four CDs, each including one segment of around 60 minutes. According to ACCA, the convenience of the CD series allows users to use it virtually anywhere - it can be used in training rooms, classrooms, at the office, or at home. In addition, each CD contains appropriate handouts for easy printing. “Understanding Manual J” uses the abridged version of ACCA’s Manual J as a teaching tool, and is designed to help HVAC professionals use load calculation programs intelligently to ensure an accurate result.

The four CDs in “Understanding Manual J” include:

Part 1 - Guidelines and Limitations:An explanation of the limitations involved with the abridged edition of Manual J8ae, a discussion of the basic principles of the abridged and unabridged 8th editions, adequate Exposure Diversity is discussed and explained as are infiltration, ventilation, and exfiltration and how to calculate the Btuh cost of each.

Part 2 - How Heat Moves and What To Measure:Heat is defined, the ways in which heat moves are discussed, density, volume, R value, U value, and Heat Transfer Multipliers are explained, sensible and latent heat are defined, what needs to be measured and how to measure it and zoning requirements are considered.

Part 3 - Design Conditions and Fenestration:Design conditions are defined and explained as are Altitude Correction Factors and Sensible Heat Gain Coefficient, load calculations are performed for windows, glass doors, skylights and shaded glass, Low E glass and NFRC rated glass are also discussed.

Part 4 - Opaque Surfaces and Duct Systems:Opaque structures are defined and load calculations are performed for walls above and below grade, ceilings, elevated floors, basement floors and slab on grade floors, solid doors, people, plants and appliances as well as duct system losses and gains, Sensible Heat Ratio and how to choose the equipment based on the load calculations are also discussed.

The CD series can be purchased at (under “New Products”) or by calling 888-290-2220. Each CD package costs $398; ACCA members can receive a 25 percent discount off the list price.

Publication date:12/03/2007