Evaporative coolers are designed to work best in areas not easily cooled by traditional air conditioning. This means ideal spaces have access to ambient air via open bays, doors or windows. While there are some environments conducive to evaporative cooling use in an enclosed building, the cooler is not going to operate at its highest efficiency. In some instances, running an evaporative cooler in a closed environment could make the room or building warmer by increasing the humidity level.