15.21 The cross section of a storm window is shown in the sketch. How much heat will be lost through a window measuring 1.83 m by 3.66 m on a cold day when the inside and outside air temperatures are, respectively, 295 and 250 K? Convective coefficients on the inside and outside surfaces of the window are 20 and 15 W/m.K, respectively. What temperature drop will exist across each of the glass panes? What will be the average temperature of the air between the glass panes? Air space 0.8 cm wide Window glass 0.32 cm thick 15.22 Compare the heat loss through the storm window described in Problem 15.21 with the same conditions existing, except that the window is a single pane of glass 0.32 cm thick. Problem 15.21 asks you to calculate the heat loss from a double pane window and 15.22 for a single pane window. Recognizing that double pane windows are more expensive than single pane windows because of the more complex