Parking Garage Ventilation Calculator
Code airflow for an enclosed parking garage.
Enter your values
Enter the garage floor area in sq ft.
Enter the ceiling height in ft.
Enter the code rate in CFM/sq ft.
Results update instantly as you type — no submit needed. Your values are remembered on this device, and the shareable link reopens the calculator with exactly these numbers.
- Required exhaust
- 15,000 CFM
- Air changes
- 5
- Fans at 12,000 CFM each
- 2
- CO-controlled low speed (50%)
- 7,500 CFM
- Annual saving with CO control
- Often 50-80% of fan energy
Quick answer
Enclosed parking garages are commonly ventilated at 0.75 CFM per square foot of floor area.
CFM = area x 0.75
At a glance
| What it does | Code airflow for an enclosed parking garage. |
|---|---|
| Category | HVAC & Airflow |
| Inputs needed | Garage floor area, Ceiling height, Code rate |
| Main output | Required exhaust |
| Formula | CFM = area x 0.75 |
| Cost | Free — no sign-up, no download |
How to use the Parking Garage Ventilation Calculator
- 1Enter the enclosed floor area and clear height.
- 2Apply your local rate — 0.75 CFM per sq ft is the common default.
- 3Add CO and NO2 sensors so fans modulate instead of running flat out.
Inputs explained
- Garage floor area(sq ft)
- Enter the garage floor area in sq ft.
- Ceiling height(ft)
- Enter the ceiling height in ft.
- Code rate(CFM/sq ft)
- Enter the code rate in CFM/sq ft.
Worked example
Using the values the calculator loads with:
Inputs
- Garage floor area20000 sq ft
- Ceiling height9 ft
- Code rate0.75 CFM/sq ft
Results
- Required exhaust15,000 CFM
- Air changes5
- Fans at 12,000 CFM each2
- CO-controlled low speed (50%)7,500 CFM
- Annual saving with CO controlOften 50-80% of fan energy
Frequently asked questions
Is CO control allowed?
Most modern codes permit demand control down to a minimum, with sensors and alarms.
Where do exhaust points go?
Split between high and low level, since CO mixes but heavier vapours settle.
What do I need to enter into the Parking Garage Ventilation Calculator?
Just 3 values: garage floor area, ceiling height, code rate. Every field starts with a realistic example, so you can change one number at a time and watch the result update instantly.
How does the Parking Garage Ventilation Calculator work out the answer?
Enclosed parking garages are commonly ventilated at 0.75 CFM per square foot of floor area. It applies the formula CFM = area x 0.75 and shows the working so you can check each step by hand.
Is the Parking Garage Ventilation Calculator free, and do I need an account?
It is completely free with no sign-up, no download and no usage limit. Everything is calculated in your browser, so the numbers you type never leave your device.
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.