AC BTU & Ton
Sizing Calculator

No. Oversized units short-cycle — they cool the air quickly but don't run long enough to remove humidity, leaving rooms feeling clammy. Undersized units run constantly and wear out faster. Proper sizing is critical for comfort, efficiency, and equipment lifespan.

The standard rule of thumb is 20 BTU per square foot, but this varies significantly by region and home characteristics. Hot climates need 25-30 BTU/sq ft, cold climates 15-20 BTU/sq ft. Insulation, ceiling height, and sun exposure all matter.

No. This calculator gives a fast estimate suitable for replacement sizing or rough planning. A proper Manual J load calculation considers every window, door, insulation R-value, infiltration rate, and orientation. For new construction or major remodels, always do a full Manual J.

Yes, the cooling load result also estimates heat pump cooling capacity. For heating sizing, the load is roughly 80-90% of the cooling load in moderate climates, but cold climates require Manual J for accuracy.