My daughter just bought a 150 yr old farm house with 30" fieldstone walls. They want to redo on room (remove lath and plaster and drywall it). They feel that they should insulate before putting up the drywall. I feel this will defeat the "U" factor which provides a heat/ cold sink. The house is in Wisconsin and we get 0 degree in winter and 90 degrees in summer.

Any advice on this project??