DIAGNOSIS Dust accumulates on the intake grille at the bottom, the fan blades, and the interior surfaces, which can reduce efficiency and cause odors.
FIX Unplug and remove the filter and shell. Use the brush attachment on your vacuum to clean the bottom intake grille. Use a damp microfiber cloth to wipe the interior plastic surfaces. For the fan, hold the blade still and wipe each blade with a cloth. Never immerse the base unit in water or use harsh cleaners.
IF THAT DIDN'T WORK For a musty smell that persists after cleaning, the issue is often in the filter itself, even if it's not due for replacement. Moisture can cause microbial growth. Replace the filter early if a smell is present.
HEADS UP Always ensure the interior is completely dry before reassembling and plugging the unit back in. Reinstall the filter and shell securely—a misaligned shell can create an annoying whistle.