I had a new furnace installed about two years ago (American Standard Freedom 95 Comfort-R). The filter has been changed by the company that installed it but their free tune ups are now over it's time to change the filter. When I opened the filter box I noticed that while there is a 4" filter installed it looks like the box could fit a 5" filter. Would it be okay to put a 5" in there? Would it add any benefit? I noticed that with the current 4" filter it does not completely seal the box and a small amount of air is able to flow around the filter. I was hoping a 5" would seal it and maybe even help efficiency or air filtration. Current filter size is 16x25x4. Thanks for your help.