ASHRAE Separates Energy and Carbon Rules in Standard 90.1 Overhaul

ASHRAE, the group that sets widely used building standards, is splitting its rules for energy efficiency and carbon emissions into two separate documents. Standard 90.1, which has guided commercial building energy efficiency since the 1970s, will stay focused on that job. A new, separate publication will cover operational carbon and greenhouse gas emissions, including provisions that were added to the 2025 edition of the standard. ASHRAE hasn't set a timeline for the new document or said whether it will be a formal standard or a guideline.

This is a commercial building standard, so it does not directly affect single-family homes or their rebate programs. But it matters because these standards often shape local building codes, which can eventually influence rules for larger residential and mixed-use buildings, and cities like New York already have their own carbon laws (such as Local Law 97) that this new framework is meant to support.

For now, this is a behind-the-scenes change in how industry rules get written, aimed at giving engineers and code writers clearer, separate playbooks for cutting energy use versus cutting carbon. The two goals often overlap but aren't identical, and mixing them in one standard had reportedly caused confusion for people designing and approving building systems. There's no new program, rebate, or deadline here for homeowners to act on.