How to clean mini-split filters (and how often by brand)

Where the filters are

On a wall unit, lift the front cover from the bottom edge until it stays up. The filters are the thin plastic-mesh screens on top, often two of them. Pull each one up and out, or down, as your manual shows. Ceiling cassettes and floor units hide them behind a grille. If the front cover won’t open easily, check the manual before you pry.

Some units also have a second, thinner filter clipped to the mesh, for odor or fine dust. LG says some of its filters must not be washed with water (LG). Some of those get replaced and some get washed on their own schedule. Your manual names them.

How to wash them

Turn the power off at the breaker.
Take the filters out and vacuum the loose dust off first. Daikin and LG both start with a vacuum or a soft brush (Daikin, LG).
If they’re still dirty, wash them in lukewarm water with a little mild dish soap, then rinse the soap out. Don’t use hot water. Mitsubishi says no hotter than 122°F (Mitsubishi), and LG’s manual calls for lukewarm water (LG). Don’t scrub with a stiff brush or put them in the dishwasher (Gree).
Let them air dry in the shade. Don’t use a hair dryer, a heater, or direct sun (Senville).
Slide them back in dry, close the cover, and turn the power back on.

Don’t run the unit without filters while they dry. Mitsubishi says that can cause a malfunction (Mitsubishi), and Fujitsu says to always run with filters installed (Fujitsu).

How often, by brand

Here is what each brand’s own page says. When your manual gives a number, use it.

Brand	What its own page says	Source
Mitsubishi	Every 2 weeks (EZ FIT ceiling cassette)	Mitsubishi help center
Daikin	Every 2 weeks	Daikin
Fujitsu	Every 2 weeks under normal use	Fujitsu manual
LG	Every 2 weeks	LG
Carrier	Inspect and clean every 4 to 6 weeks	Carrier
Gree	Once a month	Gree
Senville	Every 30 to 60 days; every 2 to 4 weeks with pets, allergies, or dust	Senville
MRCOOL	Every 4 to 6 weeks. Another MRCOOL page says every 1 to 3 months, depending on use.	MRCOOL, MRCOOL filter sizes and maintenance

ENERGY STAR’s rule fits every brand: clean them when they look dirty or when the filter light comes on (ENERGY STAR). Some units show a filter reminder light or code. That’s a reminder to clean them, not a sign that something broke.

In New Orleans, the unit runs much of the year. Start at the short end of your brand’s range and stretch it only if the filters come out clean.

Why the wash matters

A clogged filter lets less air through. Daikin says the unit then needs more electricity to cool the room (Daikin). DOE notes that dirt can get past a dirty filter and build up on the coil (DOE, archived). Mitsubishi adds that dirty filters can lead to condensation that helps mold grow (Mitsubishi). That growth on the coil and blower wheel is behind the musty kind of mini-split smell.

What these filters can’t do

Mini-split filters are coarse. DOE notes they’re usually lower-rated than central-air filters and don’t catch small particles (DOE, archived). They protect the unit from lint and hair. They don’t clean the air the way a high-MERV central filter can, and they don’t clean the coil or wheel behind them. For ducted-system filters, sizes, and MERV ratings, see what AC filter to use. For the parts behind the filter, see how to clean a mini-split.