This is a common question, and the short answer is: minimally, and it's usually not worth the effort or cost.
The science:
Evaporative coolers work through evaporation, not through cold water. The cooling effect comes from water changing from liquid to vapor, which absorbs heat from the air. The starting temperature of the water has very little impact on this process.
What actually happens with ice:
- Ice does slightly lower the water temperature
- Colder water evaporates marginally slower (less efficient)
- The cooling effect from ice melting is minimal compared to evaporation
- Once the ice melts, you're back to normal operation
- The benefit lasts only as long as the ice does
Why it's not effective:
A typical swamp cooler moves 3,000-6,000 CFM (cubic feet per minute) of air. The thermal mass of a bag of ice is insignificant compared to this volume of air. You'd need enormous amounts of ice to make a noticeable difference—and at that point, you're essentially running an inefficient air conditioner.
The math:
- 10 lbs of ice provides about 1,440 BTUs of cooling as it melts
- A swamp cooler provides 15,000-25,000 BTUs per hour through evaporation
- The ice contributes less than 10% additional cooling for a short time
What DOES make your swamp cooler colder:
Instead of ice, focus on these proven methods:
- Ensure pads are fully saturated - Dry spots reduce cooling
- Replace old pads - New pads evaporate more efficiently
- Clean mineral buildup - Scale reduces pad effectiveness
- Improve ventilation - Better exhaust = better cooling
- Reduce heat load - Close blinds, minimize heat sources
Bottom line: Save your money on ice. The physics of evaporative cooling means ice provides negligible benefit. If your cooler isn't cooling enough, the issue is likely humidity, pad condition, or ventilation—not water temperature.