I have a vinyle sided house built in 1998. It has 2x4 walls. We put a plastic vapor barrier on the inside of the walls then filled the space between the studs with batt insulation. (unfaced). The outer wall is osb with no house wrap. On top of the osb is vinyle siding.

I have a small corner of my house where a bedroom window that is broken is. I need to replace the window. That got me wondering, would it be beneficial to remove the siding in this area, replace the entire window, then cover the osb with one inch foam insulating board like you buy at lowes? Then cover with that house wrap material? Then re install vinyle siding. My thought would be to do this a little at a time over the summer until each area around the house has the additional foam board.

Is this worth doing? Will it cause a problem with window/door fit? At lowes it looked like this reflective board is only r.2. The r value goes up with a 3/4 inch air gap but I am not sure how this is done. It jumps to r 6.2 with this gap.

Just trying to make things more comfortable and lower my bills.