Short answer
A 4 ton (48,000 BTU) AC cools roughly 2,400 sq ft in a temperate climate — about 1,920 sq ft in a hot climate up to 2,670 sq ft in a cooler one. Insulation, ceiling height, sun, and occupancy shift the real figure.
Capacity
48,000 BTU
Typical room
2,400 sq ft
Hot climate
1,920 sq ft
Cool climate
2,670 sq ft
A 4 ton air conditioner is 48,000 BTU (tonnage is just BTU ÷ 12,000). At the ~20 BTU/sq-ft baseline that covers about 2,400 square feet in a temperate climate — roughly 1,920 sq ft where summers are hot, up to 2,670 sq ft in a cooler climate.
Insulation, ceiling height, sun exposure, and how many people use the room all shift the real figure. An oversized unit short-cycles and leaves the room humid, so match the capacity to the space rather than over-buying.
| Factor | Effect on the load |
|---|---|
| Floor area | ~20 BTU per sq ft cooling baseline (ENERGY STAR, 8-ft ceiling) |
| Climate zone | -15% (cold) to +25% (hot) on the cooling load |
| Insulation | Poor +15%, average no change, good -10% |
| Ceiling height | Scales with height ÷ 8 ft — a 10-ft ceiling adds ~25% |
| Sun exposure | Shaded -10% to sunny +10% |
| Occupancy & use | +600 BTU per person over two; +4,000 BTU for a kitchen |
| Climate zone | Area a 48,000 BTU unit cools |
|---|---|
| Hot (e.g. Phoenix, Miami) | ~1,920 sq ft |
| Warm (e.g. Dallas, Atlanta) | ~2,180 sq ft |
| Temperate (e.g. St. Louis) | ~2,400 sq ft |
| Cool (e.g. Chicago, Boston) | ~2,670 sq ft |
| Cold (e.g. Minneapolis) | ~2,820 sq ft |
Temperate (highlighted) is the baseline; insulation, ceiling height, sun, and occupancy shift the real coverage.
Real, widely available units in the 36,000 BTU (3 tons) and up class. Independent picks — we're not affiliated with any manufacturer or retailer and earn nothing from these links. Always match the unit's BTU to the size above.
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2–5 ton condensers
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The value leader in central AC — solid, widely serviced equipment at a lower installed cost than the premium brands.
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At this capacity you want a ducted central system — it must be sized with a Manual J load calculation and installed by a licensed HVAC contractor. There is no DIY buy-and-plug option, so get quotes from local dealers rather than buying online.
A 4 ton unit is 48,000 BTU and cools about 2,400 sq ft in a temperate climate — roughly 1,920–2,670 sq ft depending on climate, insulation, and sun.
48,000 BTU. Air-conditioner tonnage is just BTU ÷ 12,000, so 4 × 12,000 = 48,000 BTU.
An oversized AC short-cycles — it cools fast but leaves the room humid and wastes energy. If your room is well under 1,920 sq ft, size down. Enter your room in the calculator to check.