A window glass is 0.9 m wide, 1.5 m high and 4 mm thick. During winter, the temperature of the inside face of the window is 10°C, and the outside face is at -9 °C. How much thermal power is being transported through the window? (Kr = 0.84 W/m.K)
q=K(ΔT/Δx)WL=
=0.84•19•0.9•1.5/0.004 =5386.5 W