BTU Sizing Chart by Room Size
A good starting point is roughly 20 BTU per square foot:
| Room Size | Recommended BTU | Typical Use |
|---|---|---|
| 150–250 sq ft | 9,000 BTU | Bedroom, office |
| 250–400 sq ft | 12,000 BTU | Living room, studio, garage |
| 400–650 sq ft | 18,000 BTU | Open living areas |
| 650–1,000 sq ft | 24,000 BTU | Large rooms, light commercial |
| 1,000–1,200 sq ft | 36,000 BTU | Great rooms, shops |
Factors That Change Your BTU Needs
- Ceilings over 8 ft: size up — you’re cooling more air volume.
- Lots of sun or large windows: add about 10–20%.
- Kitchens: add roughly 4,000 BTU for heat from appliances.
- Hot, humid climates: lean toward the top of the range.
- Older or poorly insulated homes: size up; tight new builds can size down.
Rule of thumb: when between two sizes, a slightly larger inverter unit is safer than undersizing — but don’t jump two sizes up, or you’ll sacrifice humidity control.
Cooling More Than One Room?
A single mini split conditions one open space. To cover several rooms independently, a multi-zone system connects several indoor heads to one outdoor unit. See our guide on single-zone vs multi-zone mini splits.
Not sure what size you need?
Use our free load calculator or browse by BTU capacity.
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