Complete a Manual J load before selecting equipment

Practice the sequence you already learned for “Complete a Manual J load before selecting equipment” until the order feels automatic. Drill ACCA Manual J from HVAC-design training. A replacement furnace is not sized from the old nameplate or a square-foot rule of thumb.

1. Measure orientation, windows, and envelope insulation.
2. Estimate infiltration by the taught method.
3. Select design temperatures for the location.
4. Compute room-by-room heating and cooling loads.
5. Sum to the block load and review outliers.
6. Select equipment from the Manual S match to that load.
7. Do not upsize for future additions without a new J.
8. Do not size from the old nameplate or a square-foot rule of thumb.