A Thermopane window of area 6.8 m2 is constructed of two layers of glass, each 5.4mm thick and separated by an air space of 2 mm. If the inside is at 12?C and the outside is at ?36?C, how much heat is lost through the window? The thermal conductivity of glass is 0.8 W/m · ? C and of air 0.0234 W/m · ? C. Answer in units of kW.