HVAC contractors use a Manual J calculation to determine the heating and cooling loads of a home or building, and recommend the capacity of HVAC equipment needed.. A more complex method known as as “Room-by-Room”, breaks down the load to each room. Room-by-Room calculations are more accurate and also allow the practitioner to determine the cfm requirements for each room. The most widely accepted method to perform whole-house or room-by-room calculations is to use the ACCA Manual J …. Manual-J Heating and Cooling Load Calculations Manual J is the name for a specific protocol (often called Heat Load Calculation or Cooling Load. About LoadCalc: A load calculation program based on Manual J, designed to be quick and easy to use. It calculates the amount of heating and cooling BTU's needed for …. To design a duct system, the HVAC system designer must have completed a Room-by-Room Manual J load calculation as well as a Manual S equipment selection. All to often, duct systems are created using rule-of-thumb methods in lieu of using Manual J, Manual S and Manual D. This practice is the predominant reason for complaints of …. Manual J Load Calculation Service. Licensed - Fast - Convenient. WHAT IS A MANUAL J? Manual J is the ACCA (Air Conditioner Contractors of America) approved method of . Manual J and Manual D are calculation worksheets published by the Air Conditioning Contractors of America (ACCA). For many years, these worksheets have been the .