What Is Bi-Glass?

The Bi-Glass System® is a patented router guide tool that enables old wood window sashes to be prepared for the installation of insulated glass in a cost-effective manner.

Jim Conachen, a marketing engineer who saw the need to save old wood windows rather than throw them in the landfills, developed the tool. He obtained a U.S. Department of Energy grant to design, manufacture, and patent this router guide. The router guide became a licensed system that was leased to individuals. PBS television's This Old House featured the Bi-Glass System on two separate projects, the first in 1993.