Walls: Existing walls were uninsulated 2×4 framing 16 inches on center. The old sheetrock was left in place to save labor and dump fees. 3 inch holes were drilled between each framing member and the cavity filled with dense pack cellulose.
Over the old sheetrock, 2 inch foil faced polyisocyurate foam board was attached, joints taped, and sealed top and bottom with foam. Over this, 1×3 strapping was attached with 3 inch long screws to the original 2×4 framing and then new sheetrock is attached to the strapping. New electrical wiring was brought up from basement behind the foam with boxes mounted on strapping.
Windows: The window in this home had already been replaced with vinyl thermopane replacements. Although not high quality windows, they function well and would not be cost-effective to replace. Two different types of storm windows, an interior storm (link to storm) costing $25 and the more traditional exterior combination storm window ($55) are being tested over the first winter. Wooden window sills with sheet rock returns and bull nose (rounded) corners are less expensive than wood trim and and always get compliments.