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2024 Residential Solar Code Changes: What You Need to Know

In the ever-evolving landscape of construction and engineering, staying up to date on the latest building codes is paramount to ensuring the safety, reliability, and resilience of structures. As of January 2024, a significant shift has occurred in the United States with the transition from ASCE 7-10 to ASCE 7-16. Officially known as the American Society of Civil Engineers Standard 7-16, ASCE 7-16 represents the latest edition of the code governing minimum design loads for buildings and other structures. The transition to ASCE 7-16 brings about several key changes, impacting the way solar installers design and install solar systems.* In this article, we will delve into the most noteworthy modification introduced by ASCE 7-16 and its implications for the industry.

Treatment of Solar Panels as Attachments

The main difference this transition brings about for solar installers is that solar panels are no longer considered part of the building’s roof, like they were under ASCE 7-10. This is because ASCE 7-10 was originally published over 14 years ago, before solar panel installations had really taken off. Now, under ASCE 7-16, solar panels are thought of as items that are attached to the roof. With the advent of new wind tunnel testing and data, there is much more information about how exactly solar panels impact roofs, and therefore how they need to be designed.  

Solar Panel Wind Exposure

Now that solar panels are considered to be attachments, ASCE 7-16 also classifies them as potentially exposed to the wind and associated higher pressures. Many installers and design and engineering firms treat all solar modules that are part of an array as exposed to the wind, regardless of their location within the array and on the roof. However, this can significantly and unnecessarily increase your total bill of materials (BOM). This is because every exposed panel requires 1.5 times more attachments, or anchor points. 

Keeping Bill of Materials Low in Light of Code Changes

In order to keep the BOM as low as possible while still maintaining safety standards, Solar Letters recommends making sure that each solar panel is individually assessed for wind exposure. While many installers and design and engineering firms might label all of the panels seen below as exposed to save time, Solar Letters would conduct an assessment and only label the necessary panels as exposed. For example, the shaded panel seen on the right would be considered exposed and therefore only this panel, as opposed to all panels, would require 1.5 more attachments. Another way that Solar Letters ensures the lowest BOM is by leveraging data and automating the Solar Letters process. 

If you have any questions related to 2024 building code changes in your area and how they impact the design and installation of solar systems, get in touch with an expert at Solar Letters today. 

*States and cities have various time frames in which to adopt ASCE 7-16. Some regions that ASCE 7-16 applies to in 2024 are Houston, Wisconsin and Kansas City.


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