What type of air does an evaporative cooler recirculate across itself?

An evaporative cooler, commonly known as a swamp cooler, primarily works by drawing in outside air and passing it through water-saturated pads. As the warm outdoor air moves through these pads, it loses temperature due to the evaporation of water, which cools the air before it is circulated into the living space.

The process emphasizes the importance of outside air, as the cooler relies on the fresh air to function effectively. When assessing the role of the air being circulated, it becomes evident that the cooler does not operate with stale or recirculated indoor air, which would be more common in typical air conditioning systems.

Understanding this principle, the correct answer highlights that the evaporative cooler draws in and cools outside air, which is essential for its efficiency in lowering temperatures and increasing humidity levels in a dry climate.