=+6-13.

An exposed wall in a building in Memphis, TN, has dimensions of 10 x 40 ft (3 x 12 m) with six 3 × 3 ft (0.9×0.9 m) windows of regular double glass, 4 in, air space in an aluminum frame without a thermal break. The wall is made of 4 in. (10 cm) lightweight concrete block and face brick. The block is painted on the inside. There is a } in. (2 cm) air space between the block and brick. Estimate the heat loss for the wall and glass combination.