I recently bought a house and the home inspector told us that we have too many air filters. We have standard wall filters installed in the house and a Honeywell popup 20X25X5 filter installed in the AC unit in the garage.
The inspector told us that the AC is doing 2 times the work since it is filtered twice. So I am asking if this is true? If it is true, would you recommend that I use the filters in the wall or use the one in the AC unit. Guidance is greatly appreciated.

Usually there is one filter per system. Why you have more is a question for your contractor when they do a on site inspection.