DIAGNOSIS: The refrigerant circuit is compromised, either from a leak or a blockage, or the unit is severely ventilation-limited.
FIX: First, check the exhaust hose setup. Is the window kit installed correctly with the hose fully extended and sealed? Is the air intake grille (on the back/side) completely blocked by furniture or curtains? Restrictive airflow is the most common cause of poor cooling.
IF THAT DIDN'T WORK: If airflow is perfect, listen closely. Do you hear a hissing sound? That indicates a refrigerant leak. No hiss but the compressor runs loudly? Likely a compressor or capillary tube blockage. Both scenarios require a certified technician.
HEADS UP: Portable ACs are inherently less efficient than window units. Expecting it to cool a large, sunny room on a 95° day will lead to 'warm air' disappointment. It's for supplemental cooling.