A single glass window pane of thickness 6mm and area 1.5m2 separates the air inside a room at 25∘C from the outdoor air at 5∘C. The thermal conductivity of glass may be taken as 0.80Wm−1K−1.
(a) Calculate the steady rate of heat flow through the glass pane.
(b) Curtains drawn across the window create a nearly stationary layer of air next to the glass inside the room. Explain qualitatively how the presence of this air layer alters the total rate of heat loss from the room and state which mode of heat transfer now becomes relatively more significant.