I am replacing a window unit and want to take a different approach to the standard process. I’ve never been a fan of the “plastic accordion folding panels” and have never had much success securing said panels on the outer edges of the window opening. I’m thinking of cutting a plywood insert that will have a cutout to fit the AC unit into with the side panels fully collapsed. I can come up with a way to secure the unit to the plywood insert and can affix a plate across the top of the panel to rest against the inside of the window as the AC would. The other thing I like about this plan is the straight and smooth top and bottom sealing surfaces. Anyone already “build this better mousetrap” or have any thoughts to share about my proposed approach?

TIA
”Staying at Home” and working on home projects!
TexasFire