Free HVAC Load Calculator
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.
9,000 BTU0.75 Ton
12,000 BTU1 Ton
18,000 BTU1.5 Ton
24,000 BTU2 Ton
30,000 BTU2.5 Ton
36,000 BTU3 Ton
48,000 BTU4 Ton
60,000 BTU5 Ton
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