Thickness of insulation to make a sunroom become a 4 season room? How much do the size and # windows affect??

Question

Trying to add insulation/rebuild walls of sunroom to turn it into a room that can be us year round.

Room is 13' x 16'

Currently have 9 large windows (35" x 64") which will be replaced with new double insulated windows. Can reduce the # of windows and sizes also.

Located in Pennsylvania.

Have heat/ac and ductwork already run to room.

Answer 1

R19 in the walls, R38 in the ceilings. The less windows the better.