Topic
Sizing and Performance
How cold a swamp cooler can get you depends on physics you can calculate: airflow, pad efficiency and the wet-bulb temperature outside. These guides show the math and the rules of thumb.
Start here
How to Size a Swamp Cooler: The CFM Formula, Climate Factors and Worked ExamplesSize a swamp cooler by airflow: multiply floor area by ceiling height to get cubic feet, multiply by the air changes per hour your climate needs (about 40 in hot desert, 30 in moderate dry, 20 in mild dry areas), then divide by 60. A 1,500 sq ft home with 8 ft ceilings in Phoenix needs about 8,000 CFM.
All sizing and performance guides
- CFM Explained: What Swamp Cooler Airflow Ratings Really Mean
What CFM means for evaporative coolers: rated vs delivered airflow, static pressure, fan laws, how CFM turns into cooling BTUs, and how to measure your own.
- Wet Bulb Temperature Explained: The Number That Decides If a Swamp Cooler Works
What wet bulb temperature is, how it differs from dew point and humidity, how to find or measure it, and how to use it to predict swamp cooler supply air temps.
- Sizing Portable and Outdoor Evaporative Coolers for Rooms, Garages and Patios
How much CFM a portable swamp cooler needs for a bedroom, garage, shop or patio. Room formulas, outdoor spot-cooling rules, water use and worked examples.
- Swamp Cooler Operating Cost: What It Really Costs to Run (Power, Water and vs AC)
What a swamp cooler costs to run per hour and per month: power draw by unit type, water and bleed-off cost, worked math at $0.15/kWh and a side-by-side with AC.