When selecting a floor standing air cooler, the Airflow (measured in m³/h or CFM) is the most critical metric. For standard indoor use, a rate of 25-30 air changes per hour is recommended, while high-heat environments like factories may require 40-50 changes. Ensure the Effective Cooling Area matches your floor plan; typically, a unit with 18,000 m³/h airflow can cover 100-150 square meters. Additionally, check the Water Tank Capacity—large industrial units should have at least 60-100 liters to ensure 8-12 hours of continuous operation without refilling.