I still working on a 50+ old house and now I’m to the windows. The original windows are double hung with weights & cords. The frames, glass & sash are all in excellent condition. The problem is, in Alaska, is it gets cold somtimes. I quoted the owners a price to replace 6 windows ranging from a 2×3 picture to a 11×6, 4 unit doble hung in Anderson wood with exterior vinyl. Also included is removing interior wall covering and installing insulation, to replace the sawdust. I noticed in my most recent issue of FHB an artical on rebuilding the sash. I have been concidering replacing the sash with an energy efficant unit. Can anybody direct me to a manufacturer?