Orientation Specific Design is our new approach to Title 24. This is a great way to find construction cost-savings.
The California 2019 Building Energy-Efficiency Standards (Title 24 Part 6) is here and the compliance measures increased. In the earlier 2016 and 2013 California Title 24 Part 6 code, it was standard practice to design the community’s homes by looking at the “Worst Case” home’s conditions to streamline production. Take a look at the image in Figure 1. Here we are reviewing an example of California’s Title 24 energy compliance software results screen. The Compliance Margin, highlighted in yellow, shows the “Best Case” north facing home and the “Worst Case” east facing home.
Typically, the builder would like these numbers as close to 0.0 as possible. It means the building meets the energy code just right, anything higher means the energy features are more than the minimum state requirements. The difference between the two margins (0.3 vs. 2.9) is representing the effect orientation has on the home. Even though each house would have the same energy features, the energy performance is very different.
Orientation Specific Design (OSD)
DuctTesters is introducing the idea of “Orientation Specific Design” (OSD) and giving the builder the information. The builder will need to decide the value of using worst case design versus the savings offered by using orientation specific design. Figure 2 is an example of a 67 lot project, with relatively equal distribution of orientation for the lots. With the energy compliance done with OSD, the project can realize over $34,000 in savings. We do this by reducing the energy features on the lots where worst-case design would typically cause the homes to be over engineered.
Where OSD really shines is with projects heavily distributed to the more favorable orientations. Think tracts with long East and West running roads or townhouse projects lining up buildings to maximize occupancy. Figure 3 shows the same 67 lot project, but from an east to west running road with a court at either end. This would still typically be designed as worst case because it has lots in each orientation. In conclusion, with DuctTesters using OSD on the project, the builder can save nearly $50,000 on the energy compliance features.
BELOW ARE THE EXAMPLES
Above in Figure 1: Results screen from CBECC T24 compliance software
Figure 2 (above): Estimated Savings Projection from OSD