Cooling Load Calculator
Estimate the cooling load for a room by floor area and room type, in BTU/h, kW, and tons.
This is a rule-of-thumb estimate based on floor area only. A proper Manual J / heat-gain calculation accounts for insulation, glazing, orientation, occupancy, internal gains, and local climate data. Consult a licensed HVAC professional before sizing equipment.
How it works
- 1Enter the floor area of the room in square metres or square feet.
- 2Select the room type — each carries a per-area heat-gain factor (W/m²).
- 3The calculator multiplies area × factor for watts, then converts to BTU/h and tons (1 ton = 12,000 BTU/h).
Use cases
- Choosing an air conditioner or mini-split for a bedroom or living room.
- Comparing cooling needs across rooms when planning a central system.
- A quick sanity check against a contractor’s equipment quote.
Frequently asked questions
What is a refrigeration ton?
One refrigeration ton equals 12,000 BTU/h — the heat absorption to melt a short ton of ice in 24 hours. A 2-ton AC removes 24,000 BTU/h.
How accurate are the per-area factors?
They are rule-of-thumb values (e.g. 100 W/m² bedroom, 200 W/m² kitchen). A 30 m² bedroom gives ~3000 W ≈ 10,200 BTU/h ≈ 0.85 tons. Real loads vary 20–50% with insulation, windows, and climate.
When do I need a Manual J calculation?
For purchasing and installation, an ACCA Manual J heat-gain calculation is the standard — it accounts for insulation, window U-values and solar gain, infiltration, occupancy, and design temperatures.
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