Saving energy
K.K. writes: "I seem to recall Jean Pearce saying she put plastic sheets on her windows to keep rooms warm, but once they're there I guess you can't open the windows easily. Do you know anything about this subject? Also, where could I buy such sheets?"
Many people tape cheap plastic sheeting over glass windows for the coldest months (meaning right now). This may not be pretty, but does help keep heat inside and cuts bills.
DIY store Tokyu Hands has two manufactured products, described generally as "mado (window) gurasu (glass) kurea (clear)," that adhere to the glass in the frame so windows can still sometimes be opened.