Learn the fundamentals
The HVAC fundamentals and refrigeration cycle book explains the theory behind these calculations.
Free previewStart Your HVAC Calculation in Minutes
Enter the sensible load and temperatures to get the required airflow in clear units. The result is a preliminary engineering estimate for decision support — not a substitute for detailed design and technical review.
Free calculatorNo sign-up requiredClear units, instant results
1. Calculate the airflow
Project & Input Data
Your project criterion: enter the value from your governing code, specification or approved supplier data. No standard value is assumed.
Your project criterion: enter the value from your governing code, specification or approved supplier data. No standard value is assumed.
A standard-air default, editable for different altitude/temperature conditions.
A standard-air default, editable if needed.
Engineering Assumptions
Direct calculation — Sensible heat equation
- The supply/room temperature difference is a user-entered design criterion.
- All percentages and inputs are user-defined; the calculation is purely arithmetic and assumes no particular code or specification.
Formula Summary
- Q(m³/s) = load(kW) ÷ (ρ × cp × ΔT)
- ΔT = room temp − supply temp
Results
Enter your data and press Calculate to see the results.
Engineering Insight
A smaller supply/room temperature difference requires a larger airflow for the same load, affecting duct and fan sizing.
Recommended Action
Confirm the chosen temperature difference matches the terminal unit type before finalising the flow rate.
2. Choose your next step
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