Passive House Institute U.S. has posted detailed performance data about windows online for ready access by builders and designers.
The Certified Data for Windows program is organized by manufacturer, and includes key values such as the window’s solar heat gain coefficient, its center-of-glass U-factor, and its whole-window installed U-factor.
Each window description also includes recommendations on which climate zones and which orientation the window is best suited for. There’s also a link to a THERM file that a Passivhaus planner would use in energy modeling software.
PHIUS has been working on the program since the fall of 2012, but posted the data to its website only last week.
In a March 28 post explaining the program, its manager, Graham Wright, said, “PHIUS’s window program is moving toward a critical goal: producing data in the format that passive house consultants need, and that enables direct comparison to windows rated by other [European]-based outfits like PHI [Passivhaus Institut] or say IFT Rosenheim. Both window industry representatives and passive house designers have told us this is critical if we want to energize the market.”
While the PHIUS system makes climate-specific recommendations for different windows, Wright says it’s his understanding that the German-based Passivhaus Institut is “still pass/fail at one level.”
“Going forward,” he said, “if you hear, ‘This is a passive house window,’ people should know to ask: ‘For what climate?’ Be wary of claims about passive house windows that don’t show any numbers or label or certificate. It might just be loose talk.”