Air Changes per Hour: 40×25×12 ft room at 800 CFM
Specific conversion page with reference context, calculator, and nearby values.
On this page
40×25×12 ft room at 800 CFM converts to
4 ACH
Use this as a quick reference for Air Changes per Hour.
Value Details
Input: 40×25×12 ft room at 800 CFM
Output: 4 ACH
Browse all reference values for Air Changes per Hour
roomVolumeFt3: 12000 | cfm: 800
ACH Calculator
Calculate ACH from airflow or find required airflow from target ACH.
ACH Result
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Nearby Reference Values
| Scenario | ACH | Room Volume (ft³) |
|---|---|---|
| 40×25×12 ft room at 100 CFM | 0.5 ACH | 12,000 |
| 40×25×12 ft room at 200 CFM | 1 ACH | 12,000 |
| 40×25×12 ft room at 300 CFM | 1.5 ACH | 12,000 |
| 40×25×12 ft room at 400 CFM | 2 ACH | 12,000 |
| 40×25×12 ft room at 600 CFM | 3 ACH | 12,000 |
| 40×25×12 ft room at 800 CFM | 4 ACH | 12,000 |
Frequently Asked Questions
Common questions about Air Changes per Hour, formulas, and expected usage.
What is ACH in HVAC design?
ACH means air changes per hour and indicates how many times the room air volume is replaced each hour.
How is ACH calculated?
ACH = (CFM × 60) / room volume in cubic feet.
Can I calculate required CFM from target ACH?
Yes. Rearranging gives CFM = (ACH × room volume) / 60.
Is higher ACH always better?
Not always; target ACH depends on occupancy, use type, comfort, and energy goals.
Methodology and Review
This page is generated from the same conversion definition used by the main calculator page, which keeps the calculator, reference table rows, and FAQ schema aligned.
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Use this page as a fast lookup reference, then confirm final project values using applicable standards and manufacturer documentation.