The Net Zero Modification and Preservation Temporary Amendment Act of 2026 amends the Green Building Act of 2006 to provide exemptions for certain nonresidential projects from the requirement to maintain net zero energy compliance. Specifically, the bill allows exemptions for temporary buildings, additions under 10,000 square feet, police and emergency response facilities, natatoriums, and projects with permits submitted before October 1, 2024. Additionally, the bill modifies the definition of net-zero-energy standards and the types of projects to which these standards apply, including the introduction of new definitions such as "aquatic center" and "natatorium."

The bill also makes several amendments to existing legal language, including the replacement of "substantial improvement" with "Level 3 alterations" in various sections. It clarifies that renewable energy must be generated on-site wherever feasible and restricts on-site fuel combustion for thermal energy to backup power generation only. The act is set to take effect following approval by the Mayor and will expire after 225 days.