The short answer
Clean the filters about every two weeks: lift the front panel, pull them out, wash them in lukewarm water with a little mild detergent, dry them in the shade and slide them back. Wipe the outside of the head with a soft damp cloth. Keep leaves, snow and mulch off the outdoor unit. Leave the coil, the barrel fan and the drain pan inside the head to a tech, because the makers warn that cleaning in there wrong can cause water leaks or a shock. That routine keeps a mini split in Northern Virginia running quiet and smelling clean.
Filters: about every two weeks
Daikin, Mitsubishi Electric and LG all say to clean the filters about every two weeks. It sounds like a lot. It takes five minutes, and no other job you can do yourself helps a mini split more.
- Turn the head off with the remote.
- Lift the front panel until it stays open.
- Slide the filters out. Most wall heads have two, one on each side.
- Vacuum off the loose dust, then wash them in lukewarm water with a little mild dish soap.
- Let them dry in the shade, not in direct sun.
- Slide them back in and close the panel.
What not to do: no water over 104°F, which can warp the filter. No scrub brush, no thinner or solvent. Don’t run the head without its filters, even for a day. The dust goes straight into the coil, and that’s the part you can’t clean yourself.
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The outside of the head
Wipe the panel and the louvers with a soft cloth dampened in plain water. Skip deodorizer and cleaning sprays; Daikin’s manual warns against them. If your head’s front panel lifts off for washing, the owner’s manual shows how.
The outdoor unit
- Keep a couple of feet clear around it: no shrubs, mulch piles, leaves or stored stuff.
- After a snow, clear it off and around the unit gently, by hand or with a broom. Don’t chip at ice.
- Pull leaves and sticks off the top and out of the fins by hand.
- With the power off at the disconnect, rinse the coil gently with a garden hose. Never a pressure washer, which folds the fins flat.
Inside the head is a tech’s job
Behind the filters sit the coil, the long barrel fan that blows the air, and the drain pan. That’s where the buildup that smells and throws black specks lives. Daikin’s manual says to consult the installer for cleaning in there, and warns that cleaning it wrong can break plastic parts and cause water leaks or an electric shock. Fujitsu and Mitsubishi Electric recommend an inspection by a service tech for the same reason.
The spray and bag kits sold online put a lot of water right next to the circuit board and the fan motor. When they go wrong, the bill is a board, not a cleaning. A tech protects the board and the wall before any water goes near the coil.
Signs it’s due for a deep clean
- Black specks on the louvers, or blown onto the wall.
- A sour or musty smell for the first few minutes after it starts.
- Weaker air than it used to have, even with clean filters.
- Water dripping from the head: mini split leaking water covers that, and a head with a pump has its own list in mini split condensate pump.
- A whistle or a rattle from the fan.
What it costs
A ductless tune-up is $99 per system, the same price as a furnace or AC tune-up, and anything it finds that needs more gets a written price before any work. That covers one system, the same way it does for a furnace or an AC. If the coil and barrel fan need a deep clean, you get that price in writing first. Once a year is the usual, and spring is a good time, before the heads start making water. Our tune-up page has the rest.
A dirty system is also the start of a lot of repair calls. Mini split repair covers what breaks, and mini split making noise covers the whistles and rattles.
Book it
A ductless tune-up is $99 per system, and anything more gets a written price first. Call (703) 997-9757 or book a visit online and tell us the brand and how many heads you have. Rated 5.0 stars across 1,138 reviews on Google, Angi, Yelp, the BBB and Facebook, Virginia Class A license 2705192276.
Mitsubishi Electric, Daikin, Fujitsu and LG are trademarks of their owners.
Questions people ask
How often should I clean my mini split filters?
About every two weeks while you’re using it. Daikin, Mitsubishi Electric and LG all say about every two weeks.
Can I wash mini split filters with soap?
Yes. Lukewarm water and a little mild detergent, then dry them in the shade. Keep the water under 104°F and skip the scrub brush.
Can I clean the inside of my mini split myself?
The filters and the outside panel, yes. The coil, the barrel fan and the drain pan are a tech’s job. Makers warn that cleaning in there wrong can cause water leaks or a shock.
Why does my mini split smell when it turns on?
Usually buildup on the coil, the barrel fan or in the drain pan. Clean the filters first. If the smell stays, the inside needs a deep clean.
Should I hose off my mini split outdoor unit?
A gentle rinse with a garden hose, power off first, is fine. Never use a pressure washer. It bends the fins.
