The rate of heat conduction out of a window on a winter day is rapid enough to chill the air next to it.

To see just how rapidly the windows transfer heat by conduction, calculate the rate of conduction, in watts, through a 2.95-m² window that is 0.64 cm thick if the temperatures of the inner and outer surfaces are 5.1C and -7.5C , respectively. This rapid rate will be maintained by the interior heating of the house.