The building sector accounts for a staggering 40% of all energy consumed in the country. While existing buildings are often "grandfathered," nearly every modification – from simple repairs to significant additions – triggers complex energy code requirements under the IECC. This presentation demystifies IECC Chapter 5, which dictates how codes are applied to alterations, repairs, additions, and changes of use. The speaker will walk attendees through real-world scenarios to show exactly how the code applies to a building's envelope, HVAC, and lighting systems. Finally, discover how leveraging energy modeling provides a strategic advantage for ensuring compliance, offsetting new energy demands, and driving cost savings in challenging retrofit projects.