Double-pane glass windows, designed to reduces heat losses, consist, as the name implies, of two glass panes separated by a thin gap filled with dry air and sealed. Let’s compare the efficiency of a single-pane window (just one pane without an air gap) with that of a double-pane window with the same overall thickness of glass. The single-pane window has a surface area of 1.5 m² and the glass thickness is 0.5 cm. The doublepane window has the same area but comprises two 0.25-cm-thick glass panes separated by a 2-mm air gap. The convective heat transfer coefficients inside and outside the room are 10 and 20 W/m² K and the inside and outside temperatures are 25°C and 4°C, respectively. Compute the heat losses from the window for the two cases. In each case, also compute the temperature at the inside and outside surfaces of the window.

Assume that heat transfer occurs only by conduction in the air gap and neglect radiant heat transfer.