A picture’s worth a thousand words…
Front cover Fujitsu RLS Heat Pump
Flip cover open to reveal filters
Lift primary filter to expose small secondary filters
One filter under left and another under right
Location of secondary filters on Fujitsu mini-split heat pump
Ted's Energy Tips 
How often do you have to change filters on a Fujitsu model ASU9RLE1. Both filters.
the price is ridiculous, i asked my brother a HVAC service man who is a trained Fujitsu Heat Pump installer about these filters, he said you DON’T even need them, that in fact they restrict air flow making your unit less effecient
We have now had our ASU18RMLQ Fujitsu mini-splits for 5 years. We have had the water drip problem but hook a wet/dry vac to the drain hose outside and vacuum the hose for 1 or 2 minutes. After the interior unit started dripping dark oil, I cleaned the interior rotating fan that had clogged with mold/dust/black stuff. ( I should have removed the entire cover but I did not think of it.) I used small brushes and a toothbrush and removed probably 2 cups of crud. This maintenance is not mentioned in the owner’s manual. Now I am looking at replacing the heap filter (charcoal type K9086706004) and it costs $45.00! Recommended replacement every 2 years.
We installed an ASU12RLS Fujitsu mini split in another building 4 years ago. I have had no leaking from it but the manual recommends changing the Polyphenol Catechin Air Clean Filter and the Negative Air Ion Deodorizing Filter every 2 months. They cost $70.00 for a 2 pack! It is recommended that they be changed every 2 months. I am now searching for a better price on these filters. The Polyphenol Catechin Air Clean Filter is no longer available on sites I have searched.
We are seriously considering putting these in our new home. Would you still highly recommend it? Is their a significant cost savings? Any input would be greatly appreciated…thank you!
Love them! I just turned mine on a few minutes ago to take the nip out of the air.
While they vary in energy efficiency, even the basic ones have advantages over central systems. Not having ducts is a win right off the bat. It’s common for ducts to lose 10-30% of the efficiency.
However, you really have to look at were you live and how you use the system. Do you have any other heating systems in the house? How much space do you have to heat? And so on.