What changes the price
- Equipment capacity and efficiency
- Ductwork or electrical changes
- Number of zones
- Climate and design load
- Refrigerant-line and permit work
Scope boundary for this calculator
This worksheet treats conditioned floor area as the starting point for a whole-home heating and cooling load scenario. Its boundary is broader than furnace selection: envelope leakage, glazing, orientation, occupants, ventilation, ducts, and design weather still require a Manual J calculation. The attached cost is a planning layer for replacement scope, not an equipment schedule or permit-ready design.