HVAC Sizing Calculator
Estimate air-conditioner or heat-pump capacity in tons from conditioned area and application.
Simplified area-based estimate only. Correct sizing requires a full Manual J load calculation accounting for climate, insulation, windows, occupancy, and equipment heat gains. Oversizing causes short cycling and poor humidity control. Consult a licensed HVAC professional before purchasing equipment.
How it works
- 1Enter your conditioned floor area in m² or ft².
- 2Select the application — residential, light commercial, or server room — which sets the W/m² factor.
- 3The calculator finds the heat load and converts it to BTU/h and refrigeration tons.
Use cases
- Sizing a split-system air conditioner for a home or apartment.
- Estimating cooling capacity for a small office or retail space.
- A quick check on server-room cooling before calling a contractor.
Frequently asked questions
What is a ton of refrigeration?
One ton is 12,000 BTU/h (≈ 3.517 kW) of cooling. A typical 1500 ft² home needs roughly 2–2.5 tons.
Why does application type change the factor?
Internal heat gains differ. Residences average ~120 W/m²; light-commercial ~160 W/m²; server/IT rooms reach 400 W/m² or more.
Is this accurate enough to buy equipment?
No — it is a planning guide. A Manual J calculation accounts for climate, insulation, windows, occupancy, and ventilation. Have a licensed HVAC engineer perform a full load calculation.
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