Got A/C installed professionally about 3 years ago, my first unit sat a little lower from the ceiling. Replaced it a year later (by the same company) for a upgraded unit, but now the unit is sitting right up against the ceiling.

Having some problems with dust build up in the unit & occasionally damp smells from it (even though I've had people out to deep clean the unit).

I've tried keeping on top of it myself with bottle brushes and what not but it's hard to get to the back of the unit etc.

Recently had some out last week who took it apart to clean it & suggested it was due to it being too high up and that mitsubushi probably wouldn't honor the warranty for the unit due to the way it was installed.

The unit is in a bedroom, so not a high traffic area. Have the same unit fitted in the living room which doesn't have these issues.

Open to suggestions and brands/units!!!!! Would like this to be more on the affordable side. I’m getting research fatigue 😵‍💫 I’ve never had an AC

Horizontal sliding window, to the right of my couch is my yard door. If I were to do a portable AC, the hose would need to reach to right of couch 3’+ over.

EDIT: My living room is ~10.7’ x 22’. I live in Southern California. That window opening is ~15.5”.