AHU Capacity Calculator Guide
Calculate air handling unit capacity quickly and accurately. Improve airflow efficiency and ensure proper cooling performance.
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AHU Capacity Sizing Tool Guide
How to Use AHU Capacity Calculator Guide
Follow these simple steps to use an AHU capacity calculator:
Step 1: Enter Room Dimensions
Input length, width, and height of the room (in meters or feet). The calculator uses this to determine total air volume.
Step 2: Input Air Changes per Hour (ACH)
Enter the required ACH value. Typical values include:
- Offices: 4–6 ACH
- Hospitals: 6–12 ACH
- Labs: 10–15 ACH
Step 3: Add Occupancy Load
Enter the number of people in the space. This helps estimate heat and ventilation load.
Step 4: Include Equipment Load
Add heat load from machines, lighting, and appliances.
Step 5: Click Calculate
The AHU capacity calculator shows:
- Required CFM (Cubic Feet per Minute)
- Cooling capacity (TR or kW)
Tip: Always verify results with HVAC design standards.
How to Calculate AHU Capacity Guide
Use this formula to calculate AHU capacity manually:
Where:
- Room Volume = Length × Width × Height
- ACH = Air Changes per Hour
Step-by-Step Example
Step 1: Calculate Room Volume
Room size = 10 m × 8 m × 3 m
Volume = 10 × 8 × 3
= 240 m³
Step 2: Select ACH
Assume ACH = 6 (for office)
Step 3: Convert Volume to CFM
First convert m³ to ft³:
240 m³ × 35.3147 =
8475.5 ft³
Step 4: Apply Formula
CFM = (8475.5 × 6) / 60
CFM = 847.55 ≈ 848 CFM
Step 5: Convert to Tons of Refrigeration (TR)
1 TR ≈ 400 CFM
TR = 848 / 400 = 2.12 TR
Final Answer: AHU Capacity ≈ 850 CFM or 2.1 TR
AHU Capacity Conversion Chart Guide
| CFM | TR (Tons) | kW (Approx) |
|---|---|---|
| 400 CFM | 1 TR | 3.5 kW |
| 800 CFM | 2 TR | 7.0 kW |
| 1200 CFM | 3 TR | 10.5 kW |
| 1600 CFM | 4 TR | 14.0 kW |
| 2000 CFM | 5 TR | 17.5 kW |
| 2400 CFM | 6 TR | 21.0 kW |
Note: Values are approximate and depend on system efficiency.
FAQs – AHU Capacity Calculator Guide
An AHU capacity calculator helps you estimate airflow and cooling capacity for HVAC systems.
A typical office requires 4 to 6 ACH for proper ventilation.
Divide CFM by 400 to get approximate tons of refrigeration.
Proper capacity ensures comfort, energy efficiency, and good indoor air quality.
Yes. Use room volume and ACH to calculate CFM, then convert to TR.
Key factors include: Room size, Occupancy, Heat load, and Ventilation requirements.
No. Oversizing wastes energy and reduces efficiency.