A CFM calculator is a tool used to estimate the required Cubic Feet per Minute (CFM) of airflow for a particular application, such as heating, cooling, or ventilation. To use this calculator, you need to input details such as the size of the room or space, the number of people occupying it, and the type of activity being performed. Additionally, some calculators may ask for information on the efficiency of the HVAC system, the desired temperature, and external factors like climate and humidity. Based on these inputs, the CFM calculator will compute the necessary airflow to maintain the desired comfort level and ensure proper ventilation. This helps in selecting the right-sized HVAC equipment and optimizing energy usage.
Full Name: Cubic Feet per Minute, which refers to cubic feet per minute.
Definition: CFM is a commonly used imperial flow rate unit in the International System of Units, specifically designed to measure the volume of gas or liquid passing through a specific point within a certain time period. In the fields of fluid dynamics and engineering calculations, the CFM value is often used to quantify the amount of air that fans, air conditioning systems, and other equipment can push or pull in one minute, serving as a key indicator of their cooling performance.
Conversion Relationship: 1 CFM is approximately equal to 28.3168 liters per minute (L/MIN) or 0.0283 cubic meters per minute (m³/min).
Application Examples:
To determine the required airflow in CFM for a 2500 ft² home kitchen with a ceiling height of 8 ft and a desired air changes per hour (ACH) rate of 8.
The formula used to calculate the required airflow in CFM is:
The kitchen has a floor area of 2500 ft².
The ceiling height is 8 ft.
The desired ACH rate is 8.
Calculate the volume by multiplying the floor area by the ceiling height:
Use the formula to find the required airflow:
Use the bathroom fan size calculator
Airflow Capacity | Recommended Receiver Volume | |||
---|---|---|---|---|
(cfm) | (m³/h) | (cu ft) | (gal) | (m³) |
100 | 170 | 13 | 100 | 0.4 |
200 | 340 | 27 | 200 | 0.8 |
300 | 510 | 40 | 300 | 1.1 |
400 | 680 | 54 | 400 | 1.5 |
500 | 850 | 67 | 500 | 1.9 |
750 | 1275 | 101 | 750 | 2.9 |
1000 | 1700 | 134 | 1000 | 3.8 |
1500 | 2550 | 201 | 1500 | 5.7 |
2000 | 3400 | 268 | 2000 | 7.6 |
3000 | 5100 | 402 | 3000 | 11.4 |
4000 | 6800 | 536 | 4000 | 15.2 |
5000 | 8500 | 670 | 5000 | 19.0 |
7500 | 12750 | 1005 | 7500 | 28.5 |
10000 | 17000 | 1340 | 10000 | 38.0 |
Area (sq ft) | Required Ventilation (CFM) |
---|---|
<500 | 30-60 |
500-1,000 | 45-75 |
1,000-1,500 | 60-90 |
1,500-2,000 | 75-105 |
2,000-2,500 | 90-120 |
2,500-3,000 | 105-135 |
3,000-3,500 | 120-150 |
3,500-4,000 | 135-165 |
4,000-4,500 | 150-180 |
4,500-5,000 | 165-195 |
Building/Room | Air Changes per Hour (ACH) |
---|---|
Residential | |
Basements | 3-4 |
Bedrooms | 5-6 |
Bathrooms | 6-7 |
Living rooms | 6-8 |
Kitchens | 7-8 |
Laundry room | 8-9 |
Non-residential | |
Offices - Business offices | 6-8 |
Canteens | 7-12 |
Conference rooms | 8-12 |
Medical procedure offices | 9-10 |
Copy rooms | 10-12 |
Main computer rooms | 10-14 |
Smoking area | 13-15 |
Restaurants | |
Dining area | 8-10 |
Food staging | 10-12 |
Kitchens | 14-60 |
Bars | 15-20 |
Public places | |
Hallways | 3-5 |
Waiting rooms | 4-8 |
Banks | 4-8 |
Hospital wards | 6-8 |
Gymnasiums | 6-10 |
Malls and retail stores | 6-10 |
Lavatories | 6-15 |
Classrooms | 6-20 |
Foyers | 8-10 |
Churches | 8-12 |
Theatres and auditoriums | 8-15 |
Restrooms | 10-12 |
Swimming pools | 10-15 |
Hospital facilities | 10-20 |
Auditoriums | 12-14 |
Smoking rooms | 15-20 |
What is CFM? CFM = cubic feet per minute, is a unit of measure used for volume flow
* length * width = room's floor area — The room's floor square footage;
* ceiling height — The room's average height from floor to ceiling in feet
* ACH — Air change per hour required for the given room.
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