Product Review

High-Efficiency Commercial Window Inserts

Alpen’s WinSert commercial window inserts significantly improve the thermal performance of aging window systems, without the cost or aesthetic concerns of full replacements.

Instead of new construction, many firms are retrofitting older buildings in an attempt to reduce a project’s embodied carbon. The problem is that the operational energy required to run these often poorly insulated buildings can offset many of those gains. And windows are one of the biggest challenges, since they account for “about 10% of the energy use in buildings and influence end uses that comprise 40% of building energy use,” according to the U.S. Department of Energy.

Alpen High Performance Products is offering a solution to this problem in the form of its WinSert interior window inserts (otherwise known as a secondary glazing systems, or SGS). WinSerts have been in development for a number of years as prototypes, but Alpen is now marketing them for wider distribution. Available for commercial, multifamily, or residential applications, these inserts use the company’s thin-glass window technology (as found in the company’s triple and quad pane windows, a 2020 BuildingGreen Top 10 Product winner) and fiberglass frames to transform aging windows into high-performance units, reducing solar heat gain and air infiltration while improving whole-window thermal value.

Published April 5, 2021

Ehrlich, B. (2021, March 18). High-Efficiency Commercial Window Inserts. Retrieved from