DIAGNOSIS: The air filter is behind the front grille, which doesn't have an obvious latch. It's a simple slide-out design people often miss.
FIX: Turn unit off. Grip the sides of the entire front plastic panel (the large grille) and pull it straight towards you. It will detach. The rectangular foam filter is right behind it. Rinse under lukewarm water, let dry completely, and snap the front panel back on.
IF THAT DIDN'T WORK: If the panel won't budge, you might be pulling at the wrong spot. Focus your grip on the left and right edges, not the top or bottom. It requires a firm, even pull.
HEADS UP: Do not run the unit without the filter. It's not just for air quality—it prevents dust from clogging the evaporator coil inside, which would permanently kill cooling efficiency and is a nightmare to clean.