What Tightening Energy Codes Mean for Curtain Wall Buyers in North America
Energy codes across North America have been moving in one direction for years: tighter.
This isn't a single headline event but an ongoing shift, and for anyone specifying or sourcing curtain wall systems, the practical requirements behind that shift are becoming more specific — and harder to meet with yesterday's product configurations.
Where the tightening shows up
California's Title 24 offers a clear example of how these requirements evolve. The state's 2025 Building Energy Efficiency Standards, adopted by the California Energy Commission and in effect for permits submitted on or after January 1, 2026, largely maintained the prescriptive envelope requirements from the prior cycle for commercial buildings — a maximum U-factor of 0.41 for curtain wall and storefront systems, alongside 0.36 for fixed windows, 0.46 for operable windows, and 0.45 for glazed doors.
What's new in this cycle is a mandatory baseline layered on top of the climate-zone-specific prescriptive path: vertical fenestration in new construction must now meet a U-factor no higher than 0.47, with alterations capped at 0.58. In cooler climate zones, the maximum solar heat gain coefficient (SHGC) has also been tightened to 0.23, down from 0.25 in the previous cycle.
California is often an early mover on building energy policy, and similar tightening — through state-level codes or the International Energy Conservation Code (IECC) adoption cycle — is playing out in other jurisdictions, including New York and Washington State.
What this means for product configuration
Meeting these thresholds consistently is pushing the market toward higher-performance glazing and framing choices that were once reserved for premium applications:
Broader adoption of triple insulating glass units (IGUs) and, increasingly, vacuum insulating glass (VIG) in performance-critical applications
Continued reliance on argon or krypton gas fills and warm-edge spacers to bring U-factors down without redesigning the entire system
Thermal break design becoming a baseline expectation rather than a differentiator, since framing performance has a direct impact on whether a curtain wall system can meet code-mandated U-factors at all
This is the same direction FOWALL's thermal break curtain wall systems are engineered around — treating framing insulation and glazing performance as a single system-level problem rather than separate specifications to check off.
What this means for buyers and specifiers
For developers, architects, and contractors sourcing curtain wall systems for North American projects, a few practical implications follow:
Performance data needs to be current. A U-factor or SHGC rating that cleared code two cycles ago may not clear it today, particularly as mandatory minimums like Title 24's new baseline are layered onto existing prescriptive paths.
NFRC-certified ratings matter more than ever. Products without current NFRC certification default to less favorable values during compliance calculations, which can quietly disqualify an otherwise suitable system.
Climate-zone-specific configuration is becoming the norm, not the exception. A single standard glazing package is less likely to satisfy every project location as jurisdictions layer their own requirements on top of baseline codes.
Energy code tightening isn't a one-time event, and it isn't likely to reverse. For buyers, the practical takeaway is to treat code compliance as a moving target that needs to be checked project by project, rather than a box that, once checked, stays checked.
FOWALL will continue tracking regulatory developments across North American markets and reporting on what they mean for curtain wall specification and sourcing decisions.
