What is the U value of a wall section with R values of 19, 0.015, and 0.02?

To find the U value of a wall section, you first need to understand the relationship between U value and R value. The U value, which measures the rate of heat transfer through a building element, is the reciprocal of the total R value of that element. The walls’ R values given are 19, 0.015, and 0.02.

To calculate the total R value, you simply add these values together:

Total R value = 19 + 0.015 + 0.02 = 19.035

Now, the U value is the reciprocal of the total R value, calculated by:

U value = 1 / Total R value

U value = 1 / 19.035 ≈ 0.0525

When rounded, this U value is approximately 0.052, which correlates with the choice provided. Therefore, this choice is accurate due to the mathematical relationships established in thermal conductivity principles in building construction. Understanding that higher R values yield lower U values is essential, as it reflects better insulation and energy efficiency within a structure.