AC Tonnage Calculator
Preliminary area-based HVAC sizing · Enter room details to find the right cooling capacity
Room Dimensions
Standard is 8 ft / 2.4 m
Climate & Environment
Occupants & Openings
First 2 are included in base load
First 2 windows in base load
+1,000 BTU each
Lights + appliances in room
How the calculation works
Base LoadArea × Climate BTU/sq ft factor
Ceiling Adj.+10% per foot above 8 ft
standard
Insulation−15% (excellent) to +25% (no
insulation)
Solar Gain−10% shade to +25% very sunny
Occupants+600 BTU/hr per person above 2
Windows+1,000 BTU each above base of 2
Doors+1,000 BTU per exterior door
EquipmentElectrical load × 3.41 BTU
conversion
Fill in the room details
and tap Calculate
and tap Calculate
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