Make Your Own Storm Windows: “I know that a lot of people with older homes have resorted to using plastic on their windows to eliminate drafts. I used to do this every year too. I checked into replacing the windows, but the cost was a small fortune. So here is what I came up with.
1×2 pieces of wood
Pieces of plexi glass
4 L brackets per window
Small amount of your trim paint
Window clips, two per window (These are made by Stanley and look like big wing nuts with screws.)”