Mini Split Sizing Calculator
Determine the correct BTU size for your ductless mini split system based on room dimensions and conditions.
Recommended Size
Room Information
Load Factors
Available Mini Split Sizes
Closest Standard Sizes
Recommended Configuration
Frequently Asked Questions
How do I size a mini split system?
Mini split sizing is based on BTU (British Thermal Units) requirements. Calculate room square footage, then adjust for factors like ceiling height, sun exposure, insulation, climate zone, and number of occupants. Our calculator handles all these factors automatically.
What size mini split do I need per square foot?
General guidelines: 20-30 BTU per square foot for average conditions. A 300 sq ft room typically needs 6,000-9,000 BTU. However, factors like ceiling height, sun exposure, and insulation significantly affect requirements. Use our calculator for accurate sizing.
How many BTU for a 12x12 room?
A 144 sq ft room typically needs 5,000-7,000 BTU. For average conditions (8ft ceiling, good insulation, moderate climate), 6,000 BTU is recommended.
Is it better to oversize or undersize a mini split?
Neither is ideal. An oversized unit will short-cycle, wasting energy and not dehumidifying properly. An undersized unit will run constantly, struggle to maintain temperature, and wear out faster. Proper sizing is crucial for efficiency and comfort.
What does SEER rating mean?
SEER (Seasonal Energy Efficiency Ratio) measures cooling efficiency. Higher SEER = more efficient. Modern mini splits range from 16-25+ SEER. Our calculator helps you size correctly, but SEER affects operating cost.
How many square feet will a 12,000 BTU mini split cool?
A 12,000 BTU (1 ton) mini split typically covers 400-550 sq ft for average conditions, 350-450 sq ft for sunny rooms or poor insulation, and 500-650 sq ft for well-insulated shaded rooms.