Commercial Secondary Windows – A Solution for Existing Buildings

Recorded August 11, 2026 – Commercial Secondary Windows (CSWs) are retrofit glazing systems installed on the interior or exterior side of existing windows in commercial buildings. They are designed to improve energy efficiency and occupant comfort while reducing sound transmission and air leakage, all without requiring the expense and disruption of full window replacement. Secondary windows typically consist of an additional frame and glazing layer that creates an insulating air space between the existing and new window. CSWs can also be used to help building owners and operators meet energy reduction goals, satisfy Building Performance Standards (BPS) requirements, and downsize their mechanical systems. Commercial secondary windows are now available in many configurations that even allow for use on operable windows. There are new technologies being used in CSWs including vacuum insulating glazing (VIG) systems, multiple glazing layers, low-e coatings, and more. Please join NEEA’s Product Council Series presentation on Commercial Secondary Windows where glazing expert Tom Culp of Birch Point Consulting will provide an overview of commercial secondary windows as a solution for existing buildings. We’ll also hear from three manufacturers of CSWs: QuantaPanel, and Indow. Each will present on the various technologies they have implemented in their product offerings and how they can be used as solutions in existing buildings.

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