If the AC is cooling from its upper vent, but the room is still not getting cold, then there is a possibility that the room is probably hot or too big.
Always remember that Air conditioners only cool the room. If the temperature is above 95 degrees Fahrenheit in the outside surroundings, you need to turn on the Air conditioner for a long time, mainly when only one hose design is used to cool the Air by removing hot Air.
To boost the performance of AC and to keep your room cool, follow the below points.
Keep your vent Air hose straight: Set the position of the Air conditioner in such a way that the vent hose is straight and short so the heat gets out quickly.
Check if there are any leaks in the Air hose or not: Air travels through the portable Air conditioner vent hose, which carries heat that you are trying to throw out of the room. Sure that none of the air container vent hosen leaks back into the room.
Wrap the window: If sunlight is directly coming through the window in your room, it makes your room 10% of the warm air/heat in a room. So make sure to wrap the window in which the Air conditioner is installed—wrap the room with curtains, black plastic shed or reflective film, etc.
Check the corner of the windows for leaks: Check whether there is any gap between the frame around the window or not; otherwise, it will decrease the performance of the AC conditioner.
Close all the windows and doors of rooms in which AC is installed: If you open the window while AC is on the outside, warm/hot Air enters the room, and your Air conditioner cannot cool the room. It affects the performance of the AC.