The Evaporative Cooler CFM Calculator helps determine the required airflow, measured in cubic feet per minute (CFM), needed to effectively cool a given space using an evaporative cooler. This is essential for selecting the right size and capacity of the cooler, ensuring energy efficiency, occupant comfort, and adequate air exchange in residential, commercial, or industrial environments.
CFM is a key factor in the performance of any air delivery system. For evaporative coolers, which work by drawing air through moistened pads to lower the air temperature, sufficient airflow is critical to maintain proper cooling levels and achieve recommended air changes per hour (ACH). This calculator provides a reliable estimate using room volume and the desired air exchange rate.
Formula of Evaporative Cooler CFM Calculator
CFM = (Area × Ceiling Height × ACH) / 60
Where:
- CFM = airflow required in cubic feet per minute
- Area = floor area of the room (in square feet)
- Ceiling Height = room height (in feet)
- ACH = desired air changes per hour (typically 20–30 for evaporative cooling systems)
- Division by 60 converts hourly airflow into minutes
This formula helps users accurately size their evaporative coolers based on the volume of air that needs to be replaced to maintain a comfortable environment.
Helpful Reference Table
Here’s a quick-reference table for common room sizes, assuming a ceiling height of 8 feet and a standard ACH of 25:
| Room Area (sq ft) | Volume (cu ft) | CFM Required |
|---|---|---|
| 200 | 1600 | 667 |
| 400 | 3200 | 1333 |
| 600 | 4800 | 2000 |
| 800 | 6400 | 2667 |
| 1000 | 8000 | 3333 |
These values give a quick idea of the CFM rating you should look for when purchasing or configuring an evaporative cooler.
Example of Evaporative Cooler CFM Calculator
Let’s calculate the required CFM for a garage that measures 500 square feet with a 10-foot ceiling. The target air changes per hour (ACH) is 30 for fast cooling.
Step 1: Calculate room volume
Volume = 500 × 10 = 5000 cubic feet
Step 2: Apply the formula
CFM = (5000 × 30) / 60 = 150,000 / 60 = 2500
Result: You need an evaporative cooler rated at 2500 CFM to achieve 30 air changes per hour in this space.
Most Common FAQs
Most manufacturers recommend 20 to 30 ACH for optimal performance. Higher values are used in hotter climates or where faster cooling is needed.
No. This calculator is designed for enclosed or semi-enclosed spaces. For outdoor patios or open structures, airflow requirements vary significantly and are better handled with different design approaches.
An undersized cooler will fail to deliver sufficient airflow, resulting in poor cooling performance, higher humidity, and discomfort. Always match your cooler’s CFM rating with the calculated requirement for best results.