The right size air conditioning system is determined by a Manual J load calculation that accounts for square footage, insulation, window placement, ceiling height, sun exposure, and local climate. Sizing by square footage alone almost always leads to oversizing — which causes short cycling, poor humidity control, and higher utility bills.
What goes into proper sizing
- Total conditioned square footage
- Ceiling height and home volume
- Insulation R-values in walls, attic, and crawlspace
- Window size, orientation, and glazing type
- Duct condition and leakage
- Local climate design temperatures
The general rule of “500 sq ft per ton” is a quick estimate at best — the right answer is usually different. Our team includes a full load calculation with every AC installation quote, and we compare central systems against ductless mini-splits or heat pumps when those are a better fit.
