Mini-Split Sizing Calculator
This estimate is a starting point. Request a site assessment for mini-split installation in Phoenix so equipment can be selected for your actual space.
Use this tool to explore an initial cooling estimate. Floor area, ceiling height and insulation affect the result. Window exposure, air leakage and equipment performance in extreme heat also matter; a professional load assessment is needed before equipment selection.
Size your mini-split system correctly for your space
How This Calculator Works
- Mini Split: Sized at 12,000 BTU per 275 sq ft — ideal for garages and specific zones.
- Region: Southwest / Phoenix gets a 20% load increase for extreme summer heat.
- Square Footage: Base calculation of 25 BTU per square foot for split/package systems.
- Insulation: Excellent insulation can reduce load by 10%; poor insulation adds 20%.
- Ceiling Height: Each foot above 8ft adds ~5% to the load.
- Occupants: Each additional person above 2 adds approximately 600 BTU.
Understanding BTU & Tonnage
BTU (British Thermal Unit): A measurement of heat energy. Higher BTU = more cooling power.
Tonnage: 1 ton = 12,000 BTU/hr. Common residential sizes range from 0.75 to 5 tons.
Need Professional Sizing?
Get a free on-site consultation and accurate Manual J load calculation from our licensed experts.
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