9000 vs 12000 BTU Mini Split Sizing Guide

HVAC Sizing Guide

9,000 vs 12,000 BTU Mini Split Sizing & Selection Guide (2026)

How to choose the exact right capacity between a 9k (3/4 Ton) and 12k (1 Ton) ductless heat pump for bedrooms, offices, and open living spaces.

Choose 9,000 BTU (0.75 Ton): For spaces 300 to 450 sq ft (standard bedrooms, home offices, nursery rooms, or well-insulated guest rooms).
Choose 12,000 BTU (1.0 Ton): For spaces 450 to 650 sq ft (master bedrooms, living rooms, studio apartments, or rooms with high ceilings/sun exposure).
Voltage Difference: 9,000 BTU units are available in both 115V (standard plug) and 208-230V. 12,000 BTU units are predominantly 115V or 208-230V depending on SEER2 rating.

Square Footage Comparison Matrix

Room Size (Sq Ft)	Recommended BTU	Tonnage Equivalent	Typical Room Type
200 - 350 sq ft	9,000 BTU	0.75 Ton	Small Bedroom / Office
350 - 450 sq ft	9,000 - 12,000 BTU	0.75 - 1.0 Ton	Standard Bedroom / Dining
450 - 650 sq ft	12,000 BTU	1.0 Ton	Master Suite / Living Room