DIAGNOSIS The air filter is behind the rear grille, not the front. It’s a common point of confusion and if it's clogged, performance plummets.
FIX Unplug the unit. The filter is accessed from the back. Look for the large plastic rear grille. You should see two finger slots or tabs at the top. Pull the entire grille straight off. The washable foam filter is right behind it. Rinse it under lukewarm water, let it dry completely, and snap everything back.
IF THAT DIDN'T WORK If the grille seems stuck, double-check there aren't any screws holding it on (some models have them at the bottom). Don’t force it. If the filter is damaged, you can run the unit temporarily without it, but order a replacement immediately.
HEADS UP Clean this filter at least every two weeks during constant use. A dirty filter is the #1 cause of ‘my dehumidifier isn’t pulling water anymore’ complaints. Set a calendar reminder.