Ductless mini-split air conditioners have a lot going for them. They are relatively affordable, easy to install, and quiet. One common complaint about these units, however, is that they sometimes start to smell. The good news is that the most common causes of stinky mini-splits are fairly easy to address. There are some causes you can address yourself and others that require help from an AC repair person.
Ductless mini-splits are fully electric. Sometimes, one or more of the electrical components inside starts to arc or fail. A conductor may begin wearing out, or a rodent may chew some wiring. Usually, this causes an odor that reminds you of white vinegar or something slightly metallic. If that's how you'd describe your mini-split's stink, turn it off and call an HVAC repair company. They can run some simple tests to see whether you do, indeed, have an electrical problem. Most electrical problems, such as separating wires or replacing a worn contactor, are fairly easy for them to repair.
Clogged Condensate Tubes
Ductless mini-splits generate condensation as they work. This is moisture that they have pulled out of your home's air to reduce the indoor humidity levels. Sometimes the tube that is supposed to carry the condensate away from the AC unit becomes clogged. Then, two things tend to happen. Water pools around the unit, and mold starts growing inside the AC unit. You then notice a musty, dirty odor every time your AC kicks on.
An HVAC contractor can replace the clogged drain tube. This tubing is very inexpensive, so it's not often worth cleaning. They can also disassemble and clean the interior of your unit to get rid of mold.
When was the last time you changed the filter on your mini-split system? If it has been more than a couple of months, then you might be noticing a dusty, dirty odor when your AC runs. Simply pull the old filter out and put a new one into place. If that does not make the air smell fresher, contact your AC contractor. There may be some mold or grime inside the AC unit contributing to the smell. Changing your filter more often will prevent this from happening again.
If your ductless mini-split system is blowing out smelly air, it is important to figure out why. Explore the options above; they explain most cases of nasty odors. Reach out to air conditioning services near you to learn more.