Manual J is the ACCA-standard load calculation. We model your actual home: square footage, orientation, windows, insulation levels, infiltration, local 99% and 1% design temperatures, and compute the heating and cooling load for every room. It's the foundation everything else is sized from, and the document your permit office asks for by name.
SELECTION CHECKED AGAINST ACCA MANUAL S® SIZING LIMITS · MANUFACTURER PERFORMANCE DATA
A load number alone doesn't buy equipment. Manual S selects specific units from real manufacturer performance data, at your design conditions rather than the nameplate rating, and verifies the capacity lands inside ACCA's allowed sizing range. No guessing between the 3-ton and the 4-ton.
The best equipment underperforms behind an undersized duct system. Manual D sizes every trunk and branch to deliver each room's exact airflow, with friction rate and static pressure targets that keep the blower inside its comfort zone and the house quiet.
Not sure what your permit office wants? Start here, or just send us the permit requirements and we'll tell you.
Most equipment-swap permits require a Manual J load calculation. If you also want the exact replacement unit verified against manufacturer data (instead of matching the old tonnage), add Manual S. Oversized replacements are the most common, and most avoidable, mistake.
Don't have every spec? Send what you have. We confirm the remaining inputs with you before the calculation starts, so the report reflects your real house.
PDF or DWG with room dimensions, hand-drawn works too if it's legible and to scale.
Sets the local design temperatures, the climate data your jurisdiction expects to see.
U-values, R-values, window schedules, anything you have sharpens the numbers.
Forward what your permit office asked for and we'll match the deliverables to it.