I have a 4 ton Carrier central A/C heat pump with two (2) 20x20 return grilles. Each one holds a typical 20"x20"x1" filter. Yes, I use the high-end 3M filters that get virtually everything. Even when the filters are clean, they slap in pretty hard when I pull them out and release.
I've seen 4" deep filters of the same size and I'd like to replace my existing set up with two of them. Would it be a good idea or would the extra air volume reduce the evaporator's ability to remove moisture?
Would it be a good idea for the tech to reduce the speed of the fan motor if I get the 4" filters? Perhaps I can get the same air volume with less power to the fan motor and save on my electric bill.