The OEM replacement filter for my HVAC system fit perfectly. Sometimes replacement filters are a bit out of whack. I would recommend Filter Buy for any OEM replacement filters.
Cardboard tabs in filter frame are poorly cut and pooly bent so as to obstruct air flow.Filters are not labeled as to MERV rating, just the packing slip is.I suspect all the filters of this size are the same MERV as I have 20x20x5 of two different MERVs bought on seperate occaisons and they appear identical. and have no marking on the filters.
I replace my whole house filters every 6 months. I probably could get away with every year since there are no pets or kids but at these prices I don't see the need. As long as they maintain this service and these prices I'm all in.