Consider an electrically heated house whose walls are 9 ft high and have anR-value of insulation of 13 (i.e., a thickness to thermal conductivity ratio ofL/k = 13 hft2 °F/Btu). Two of the walls of the house are 40 ft long and theothers are 30 ft long. The house is maintained at 75 °F at all times, while thetemperature of the outdoors varies. Determine the amount of heat lost throughthe walls of the house on a certain day during which the average temperature ofthe outdoors is 45 °F. Values of heat transfer coefficients for combinedconvection and radiation are 1.46 BtuJhft2 °F for the inner surface of the walls,and 4.0 Btu/hft2 °F for the outer surface of walls.