Evaporative cooling, explained properly
Cooler air, lower bills, fewer repairs.
Clear, practical guidance for swamp cooler owners: how to size one, where it works, how to keep it running and how to fix it when it stops.
What is your cooler doing?
Browse by topic
- TroubleshootingStart from what you can see, hear or smell.
- MaintenanceA swamp cooler is a simple machine that punishes neglect.
- Cooler Pads and MediaThe pads are where the cooling happens.
- Pumps and WaterWater management separates a cooler that lasts three seasons from one that lasts fifteen.
- Motors, Belts and BlowersThe blower assembly moves thousands of cubic feet of air every minute.
- Sizing and PerformanceHow cold a swamp cooler can get you depends on physics you can calculate: airflow, pad efficiency and the wet-bulb temperature outside.
- WinterizationA cooler left wet over winter cracks fittings, splits lines and leaks heat out of your house all season.
- Types of Evaporative CoolersEvaporative cooling covers everything from a tabletop portable to a two-stage rooftop unit.
- InstallationMost performance complaints trace back to installation: undersized ducts, no path for air to leave, or a unit pulling hot roof air.
- Climate and HumidityAn evaporative cooler is only as good as the dry air feeding it.
- Brands and BuyingBrands differ in cabinet material, media, controls and parts support more than in basic cooling physics.
- PartsKnow the parts and you can fix almost anything on a swamp cooler with basic tools.
Essential reading
- TypesHow Evaporative Coolers Work (Physics, Parts and Real Numbers)
How a swamp cooler turns water into cooling: latent heat, wet bulb limits, pad efficiency, airflow and every working part, with worked numbers for real homes.
- SizingHow to Size a Swamp Cooler: The CFM Formula, Climate Factors and Worked Examples
Size a swamp cooler in five steps: CFM = sq ft x ceiling height x air changes / 60. Climate air change rates, duct loss margins and worked examples by city.
- PadsAspen vs Rigid Media Pads: Which Is Better for Your Swamp Cooler?
Aspen vs rigid media swamp cooler pads compared with real numbers: saturation efficiency, supply air temperature, 10-year cost, water use and conversion.
- ClimateDo Swamp Coolers Work in Humidity? Where the Cutoff Really Is
How humidity limits swamp cooler performance, the wet bulb and dew point cutoffs that matter, worked supply-air and indoor RH math, and tactics for humid days.
- TypesSwamp Cooler vs Air Conditioner: An Honest Side-by-Side Comparison
Swamp cooler vs AC compared on running cost, install cost, comfort, humidity, water use and climate fit, with worked monthly cost math and a decision table.
- MaintenanceSwamp Cooler Maintenance Schedule: What to Do Monthly, Seasonally and Yearly
A complete swamp cooler maintenance schedule: weekly checks, monthly cleaning, pad changes, belt and pump service, spring and fall tasks, and time estimates.
Original data
The Swamp Cooler Climate Index
We calculated how cold an evaporative cooler can make the air in U.S. cities on a hot design day, using design dry-bulb and coincident wet-bulb temperatures with aspen and rigid media. Find out whether your city is excellent, good, marginal or a poor fit before you buy.
See the climate index- Phoenix, AZ
- 110°F outside, about 75°F supply
- Denver, CO
- 91°F outside, about 63°F supply
- Houston, TX
- 96°F outside, about 79°F supply
Seasonal jobs
- MaintenanceSwamp Cooler Spring Startup Checklist: How to Get Your Cooler Ready for Summer
Step-by-step spring startup for a roof swamp cooler: safety, cleaning the pan, pads, water line, float, pump test, belt tension, motor oiling, and final checks.
- WinterizationHow to Winterize a Swamp Cooler (Fall Shutdown Step by Step)
Winterize a swamp cooler step by step: shut off and drain the water line, drain and clean the pan, unplug the pump, cover the unit and seal the duct.
- ClimateRunning a Swamp Cooler During Monsoon Season
How the Southwest monsoon affects swamp coolers: dew point thresholds for running or switching off, hour-by-hour tactics, dust storm care and backup cooling.
- PadsHow to Replace Swamp Cooler Pads, Step by Step
Step-by-step guide to replacing swamp cooler pads: measuring, cutting aspen, seating pads without gaps, installing rigid media correctly, tools and time needed.
- WinterizationWhen to Winterize a Swamp Cooler (and When to Start It Again), by Region
When to winterize a swamp cooler where you live: typical freeze windows by Western region, monsoon timing, a simple decision rule and spring restart dates.
- MaintenanceHow to Clean a Swamp Cooler: Pan, Pads, Pump, Distribution and Scale
How to clean a swamp cooler safely: drain and scrub the pan, remove scale with vinegar, clean the pump and spider, rinse pads and stop musty odors.
Why trust Swamp Cooler Guide
- Physics first. Every performance claim traces back to psychrometrics, airflow math or manufacturer documentation, and we show the formulas.
- Independent. No manufacturer pays for coverage or placement. Brand guides describe what each maker is known for, not who paid most.
- Kept current. Guides carry an updated date and are revised when parts, prices or guidance change. Corrections are logged publicly.