Uses the same engine as the full calculator (occupants 2, one large window assumed).
| Cooling load | — |
Common 4,500 sq ft floor plans: 60×75 ft, 50×90 ft, 45×100 ft, 36×125 ft. The load depends on area, not shape.
US (whole home): cooling load does not scale linearly with floor area. The building envelope — roof, exterior walls, windows — grows with the perimeter, which rises more slowly than area, so larger homes need fewer BTU per square foot. At 4,500 sq ft the rate works out to about 17.2 BTU/sq ft, giving a design load of 77,300 BTU/hr → 2 × 3.5 ton systems. A single residential split system stops at 5 tons, so a home this size takes 2 separate systems — typically one per floor or wing — rather than one oversized unit with dampers.
| US climate zone | Cooling load | System |
|---|---|---|
| Zone 1 — Hot (FL, S.TX, AZ desert) | 98,400 BTU/hr | 2 × 5 ton |
| Zone 2 — Warm (Deep South, TX) | 87,800 BTU/hr | 2 × 4 ton |
| Zone 3 — Moderate (TN, NC, MO) | 77,300 BTU/hr | 2 × 3.5 ton |
| Zone 4 — Mild (Mid-Atlantic, PNW) | 70,300 BTU/hr | 2 × 3 ton |
| Zone 5 — Cool (Upper Midwest, New England) | 63,200 BTU/hr | 2 × 3 ton |
India (whole home): 4,500 sq ft is past the point where one split per room stays practical — that would be 17 outdoor units. A ducted or VRF system is the normal choice. Connected load across the rooms is about 26.5 ton; applying a 70% diversity factor (rooms do not all peak together) gives a design load of about 18.5 ton.
| Room | Approx. area | Split size |
|---|---|---|
| Hall / living | ~1,260 sq ft | 2.5 ton |
| Bedroom 1 | ~129 sq ft | 1.5 ton |
| Bedroom 2 | ~129 sq ft | 1.5 ton |
| Bedroom 3 | ~129 sq ft | 1.5 ton |
| Bedroom 4 | ~129 sq ft | 1.5 ton |
| Bedroom 5 | ~129 sq ft | 1.5 ton |
| Bedroom 6 | ~129 sq ft | 1.5 ton |
| Bedroom 7 | ~129 sq ft | 1.5 ton |
| Bedroom 8 | ~129 sq ft | 1.5 ton |
| Bedroom 9 | ~129 sq ft | 1.5 ton |
| Bedroom 10 | ~129 sq ft | 1.5 ton |
| Bedroom 11 | ~129 sq ft | 1.5 ton |
| Bedroom 12 | ~129 sq ft | 1.5 ton |
| Bedroom 13 | ~129 sq ft | 1.5 ton |
| Bedroom 14 | ~129 sq ft | 1.5 ton |
| Bedroom 15 | ~129 sq ft | 1.5 ton |
| Bedroom 16 | ~129 sq ft | 1.5 ton |
Only cool the rooms you use. Sizing every room at once is how Indian households end up with two unused units and a higher connected load than the sanctioned supply allows — check your meter's sanctioned load before adding the last unit.
Figures assume 8 ft ceilings (9.5 ft for India), average insulation and normal sun. Your real number can swing ±30% — run the full tonnage calculator with your actual room data.
| Area | US | India |
|---|---|---|
| 3,500 sq ft | 2 × 3 ton systems | ducted or VRF, ~14.5 ton design load |
| 4,000 sq ft | 2 × 3 ton systems | ducted or VRF, ~16.5 ton design load |
| 4,500 sq ft | 2 × 3.5 ton systems | ducted or VRF, ~18.5 ton design load |
| 5,000 sq ft | 2 × 4 ton systems | ducted or VRF, ~20.5 ton design load |
0.75 ton 1 ton 1.5 ton 2 ton 2.5 ton 3 ton 3.5 ton 4 ton 5 ton
About 77,300 BTU/hr of design load in a moderate US climate — a 2 × 3.5 ton systems.
Residential split systems are not made above 5 tons. A 77,300 BTU/hr load has to be split across 2 systems, which also lets you zone floors independently.
A ducted or VRF system of about 18.5 ton design load. 17 separate splits would be impractical at this size.
100 sq ft 120 sq ft 150 sq ft 180 sq ft 200 sq ft 250 sq ft 350 sq ft 400 sq ft 450 sq ft 500 sq ft 600 sq ft 700 sq ft 800 sq ft 900 sq ft 1,000 sq ft 1,100 sq ft 1,200 sq ft 1,300 sq ft 1,400 sq ft 1,500 sq ft 1,600 sq ft 1,800 sq ft 2,000 sq ft 2,200 sq ft 2,400 sq ft 2,500 sq ft 2,800 sq ft 3,000 sq ft 3,200 sq ft 3,500 sq ft 4,000 sq ft 4,500 sq ft 5,000 sq ft
How these figures are derived: BTU per square foot, honestly · refine for your exact room with the full tonnage calculator.