Air Conditioner Capacity Estimator
This rough screening estimate combines floor-area load, occupant allowance and an additional heat-load allowance to suggest an initial cooling capacity range.
How to use this calculator
- Enter floor area, base watts per square metre, occupant count and other heat load.
- Confirm that all inputs use the stated units and the same population, period or scope.
- Change one assumption at a time when comparing scenarios.
Formula used by the air conditioner sizing calculator
Estimate = area × W/m² + occupants × 100 W + extra load
- Estimate = area × W/m² + occupants × 100 W + extra load
- Not a professional load calculation. Climate, glazing, orientation, ventilation, insulation and equipment loads can dominate.
- Inputs are validated against required ranges and outputs are rounded for readability.
Worked examples
Worked example
A 25 m² room at 100 W/m², two people and 300 W extra load.
The rough starting estimate is 3,000 W; use the calculator output for the exact sum.
The rough starting estimate is 3,000 W; use the calculator output for the exact sum.
Understanding the result
This rough screening estimate combines floor-area load, occupant allowance and an additional heat-load allowance to suggest an initial cooling capacity range.
Not a professional load calculation. Climate, glazing, orientation, ventilation, insulation and equipment loads can dominate.
Important notes
Not a professional load calculation. Climate, glazing, orientation, ventilation, insulation and equipment loads can dominate.
Use the result as a calculation aid for the inputs supplied; confirm critical specifications independently.
Frequently asked questions
Can I buy an AC from this number alone?
No; use a qualified HVAC assessment and local conditions for final equipment selection.
Why is the estimate rough?
It simplifies many building and climate factors into a few user-entered assumptions.
How do I use this calculator?
Enter floor area, base watts per square metre, occupant count and other heat load.
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Related explanations
Learn the method behind the number or compare the terminology before using the calculator.
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This page provides a calculation tool plus explanatory information so you can understand what the result means and when the underlying method may not fit your situation.