What does Manual J, Manual D, and Manual S collectively help you determine?

• A. Load calculation (Manual J), duct sizing (Manual D), and equipment selection (Manual S)
• B. Electrical calculations, duct leakage tests, and voltage drop estimates
• C. Ventment, combustion air, and gas line sizing
• D. Refrigerant charge estimation, coil sizing, and filter replacement

Answer: (A)

Manual J determines the space’s heating and cooling load, taking into account climate, insulation, windows, occupancy, and internal gains. Manual D uses that load to design the duct system, sizing and routing ducts to deliver the correct airflow with minimal losses. Manual S then selects the equipment—furnace, air conditioner or heat pump, and coils—that can meet the calculated load and work with the designed duct system. Put together, these manuals show what size system is needed, how air should be moved, and which equipment to install for proper performance and efficiency. The other options describe electrical work, duct leakage tests, voltage drop, venting or gas-line sizing, or coil and refrigerant tasks that aren’t the focus of these manuals.