A room has a wall with an R value of 18 F sq. ft. hr/BTU. The room is 15 feet long and 11 feet wide with walls that are 9 ft high. On a particular day the average outside temperature is 40 degrees F. How much heat is transferred through the walls on that day (in BTUs) ?

The heat transferred through the wall that day is 13728 BTUs

Explanation:

Here, we have the area of the wall given as

Area of wall = 2 * Length * Height + 2 * Width * Height

Length = 15 feet

Width = 11 Feet and

Height = 9 feet

Therefore, the area = 2*15*9 + 2*11*9 = 468 ft²

Temperature difference is given by

Average outside temperature - Wall temperature = 40 - 18 = 22 °F

Therefore the heat transferred through the wall that day (24 hours) at 18 sq. ft. hr/BTU is given by;

468 * 22 * 24/18 = 13728 = 13728 BTUs.