Your grandmother is concerned about reducing her winter heating bills. Her strategy is to loosely fit rigid polystyrene sheets of insulation over her double-pane windows right after the first freezing weather arrives in the autumn. Identify the relevant heat transfer processes on a cold winter night when the foamed insulation sheet is placed a. on the inner surface
b. on the outer surface of her window
c. when no insulation is used.

Sketch a temperature profile through each layer for each case, including for the case with no thermal insulation. For simplicity, assume a linear temperature profile through the air gap. To avoid condensation damage, which configuration is preferred