I have an 90+ year old house in BalaCynwyd, the first train stop on the Main Line outside of Philly. The house is three stories with the first story being a stone foundation and the two top floors being a Tudor stucco. I am redoing every room in the house, and on some outside walls I have been taking the lathe and plaster out, insulating and then dry walling. I will not be able to do this on all of the outside walls however- Question is what do you do to insulate-- there is none right now and the air just blows in-- heating bills are enormous. Do you cut a hole on top of the wall between the studs and blow insulation in?/ What type is best as the house is also knob and tube electrical wiring. Is spraying foam possible and better. Your advice would be greatly appreciated.