North Carolina State Mechanical Code requires that all NEW homes have a Manual D, J & S performed before any Heating & Cooling System is installed.**
Mechanical Code also requires that all EXISTING homes (requiring replacement of heating & cooling equipment) have a Manual J & Manual S performed prior to the replacement of the old units.**
Manual J: Heating & Cooling Load Calculations (Step 1)
Manual S: Selecting the right size equipment for the house (Step 2)
Manual D: Designing & Installing the correct Duct System that delivers the right air flow to every room (Step 3: for new homes only)
Typically the Manual J, S & D calculations are performed using computer-aided software. The use of these software programs require specialized training and knowledge of the heating & cooling industry to properly implement the computer results to correctly size the right unit for your particular house.
** State Code requires ACCA Manual J, S & D or other APPROVED Calculation Methodologies.