My location: Oklahoma City, OK
My home build year: 2004
Home size: ~1900 square feet, single story, abundant 10' ceilings

This summer I moved into a "new" home that was built in 2004. The home has a carrier heat pump and furnace and all ductwork up in the attic. There are 2 return air grates on opposite ends of the house on the ceiling.

Based on my measurements, the furnace filter grate size is probably 14"x24"x1", but I have yet to find a commercially produced filter in this size that actually fits.

I know the dimensions are actually something like 13.7"x23.7"x.75" but the only way I can get ANY filter to fit is by bending 2 of the edges so it'll flex enough to fit in the space. In my opinion, this means the filter is not fitting flush against the edges and unfiltered air is bypassing into the air handler.

It may only be cosmetic, but it drives me nuts. My last house, which was half the size of this one, had a single 20x30x1 return and every filter I bought fit perfect every time. This surely isn't so complicated that the ones in my new home just won't work, right?

Could this be an issue with this particular size, such that it's hard to get the manufacturers to agree? Can I or should I increase the size of the returns and in the process hopefully get a fitting pair with the furnace filter?