What size air conditioner for 600 sq ft? BTU answer and adjustments
The 600 sq ft answer: 12,000 BTU/h baseline (= 1.00 tons = 3.5 kW), 13,200 with strong sun, 10,800 in shade, 16,000 for a kitchen, 13,200 with four regular occupants. The formula is transparent — floor area × 20, then the ENERGY STAR adjustments.
| Scenario | Rule | BTU/h |
|---|---|---|
| Baseline room | 600 × 20 | 12,000 |
| Very sunny | +10% | 13,200 |
| Heavily shaded | −10% | 10,800 |
| Kitchen | +4,000 | 16,000 |
| Four regular occupants | +600 × 2 | 13,200 |
Conversions: 12,000 BTU/h = 1 ton = 3.517 kW. 12,000 BTU/h ≈ 1.00 tons ≈ 3.5 kW. Figures are cooling capacity to look for on the spec sheet, not electrical input.
Which unit, in practice
For 600 sq ft, shop for a 12,000–14,000 BTU window unit or a 12k mini-split head. If you land between sizes in a humid climate, choose the smaller inverter model — longer cycles remove more moisture, and moisture is most of the discomfort.
Related: BTU sizing explained, window vs portable, and for whole-house equipment the central AC guide. Metric version: puissance par m² (French).
Frequently asked questions
How many BTU for 600 square feet?
12,000 BTU/h as a baseline (20 BTU/sq ft), 13,200 for a very sunny room, 10,800 for a shaded one, plus 4,000 for a kitchen and 600 per occupant beyond two. That is about 1.00 tons or 3.5 kW.
What size AC unit is that?
A 12,000–14,000 BTU window unit or a 12k mini-split head. For whole-house systems serving several enclosed rooms, a Manual J load calculation replaces this room-level rule.
Is 20 BTU per square foot always right?
It is the room-unit baseline ENERGY STAR and the DOE use; ceiling height above 8 ft, poor insulation and big west glazing push it higher, while a well-insulated shaded room can sit lower. The adjustments above capture the common cases.