If your main heat problem is the single-pane windows, perhaps you could use the bubble-wrap trick? https://www.builditsolar.com/Projects/Conservation/bubblewra

If your main heat problem is the single-pane windows, perhaps you could use the bubble-wrap trick? https://www.builditsolar.com/Projects/Conservation/bubblewrap.htm https://www.builditsolar.com/Projects/Conservation/bubblewra...