basic rule of thumb for filter area is MINIMUM of 200 square inches per ton of cooling.
you have 180.
I STRONGLY recommend getting the inches above 200/ton. I prefer 360/ton for long quiet filter life, and ability to use pleated filters.
DO NOT USE 1" PLEATED FILTERS with less than 300 square inches per ton.
The TRUE highest cost system is the system not installed properly...
Do you go to a boat repairman with a sinking boat, and tell him to put in a bigger motor when he tells you to fix the holes?
I am yourmrfixit