I'm running into 2 issues:
1) The size of the return air vent (I think that's what it's called?) is fairly unusual (7.5"x23.5x1) so it's difficult to find filters for it, and
2) Filters are expensive!
I've been reading about permanent electrostatic filters - not very expensive, I think they even sell kits to make whatever size you want?
Does anyone know about the pros and cons of this, or has done it and can share tips? Supposedly there are companies that will custom make these for you, but I have no idea if they're reliable or not....