Portable air coolers, also known as evaporative coolers, work by drawing in warm air, passing it through water-saturated pads, and then releasing cooled air into the room. Unlike traditional air conditioners, they do not require a window for the expulsion of hot air. However, they do require a certain level of ventilation to be effective.
Portable air coolers work best in areas with good air circulation and ventilation. When using a portable air cooler, you should leave a door or window partially open to allow the hot air and humidity to escape. This way, the cooler can bring in fresh, dry air to continue the cooling process. If there is no way for the hot air to escape, the cooling effect will be limited, and the humidity in the room may increase, leading to discomfort.
In regions with high humidity, the effectiveness of evaporative coolers can be reduced as they add moisture to the air, which can lead to a sticky and uncomfortable environment. In such cases, using an air conditioner with proper ventilation might be a better cooling solution.
To summarize, while portable air coolers don't require a window for hot air expulsion, they do need some degree of ventilation to be effective. Leaving a door or window open slightly is recommended to ensure proper air circulation and cooling efficiency.