A house wall consists of an outer layer of common brick 10 cm thick (k = 0.69 W/m0C), followed by a 1.25 cm layer of Celotex sheathing (k = 0.048 W/m-C). A 1.25 cm layer of sheetrock (k = 0.744 W/m0C) forms the inner surface and is separated from the 51 sheathings by 10 cm of air space. The air space has a unit conductance of 6.25 W/m-C. The outside brick temperature is 50C; the inner wall surface is maintained at 20°C. 

What is the rate of heat loss, per unit area of the wall? 

What is the temperature at a point midway through the Celotex layer?