How is the exterior wall area calculated for the case study home?

The calculation of the exterior wall area is based on assessing the overall dimensions of the walls that contribute to the building's thermal envelope. The correct method of calculating this area involves multiplying the perimeter of the home by the ceiling height. This calculation provides an accurate representation of the total surface area of the walls that are exposed to external conditions, which is critical for evaluating energy performance in a home.

This method takes into account the continuous nature of the walls around the perimeter without needing to individually measure each wall segment, thus simplifying the process and ensuring a comprehensive approach to understanding the thermal characteristics of the entire structure. By using the perimeter instead of individual wall lengths, this method captures the contributions of all walls surrounding the conditioned space.

The other approaches are less effective for a comprehensive assessment. Some may only consider certain sections of the walls rather than the total exposed area, which is essential for conducting energy audits and ensuring accurate HERS scoring.