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Received an Innovative Commercialization Grant
from the U.S. Department of Energy in 1991

Learn More About Bi-Glass Systems

The Bi-Glass System replaces single-pane glass with high-quality, insulated glass, while still retaining your old sash. Reusing your old sash saves money and maintains the architectural integrity of your house. After adding custom-made, compressible jambliners, new weatherstripping, and locks, you will have a truly energy-efficient window unit that, in addition to keeping you warm and comfortable, will tilt in for easy cleaning and maintenance. Learn more about our insulated glass window system and how this window conversion process can benefit your home by contacting us in Boston, Massachusetts.


White Windows

Here's How It Works

In a Bi-Glass conversion, your original window sash is removed from the frame by a trained technician. The sash is taken outside your home to a mobile workshop. Here, the technician uses a tool to route out the old window putty and glass. This makes room for the new, insulated glass, which is installed using glazing tape and caulking. The interior muntins (grill work) always remain intact and virtually unchanged. On the exterior of the glass, we apply a muntin that matches the interior grid, thereby retaining the authentic look of your original, single-glazed window. In addition, we install new jambliners, hidden balances, weatherstripping, insulation, and locks to eliminate all drafts. The sashes are then reinstalled into their openings and adjusted to fit snugly.

A Bi-Glass System gives you state-of-the-art energy efficiency, while retaining the character of your windows. With this system, your windows are efficient, double-glazed, tiltable units, comparable to commercially manufactured wood windows.


Customizing & Condition Are No Problem!

Because we use existing wood sash, odd-sized windows present no problem. We simply custom size the new glass. We offer a variety of different balance systems, from hidden balances cut into the sash to vinyl compressible sash balances that reduce infiltration and allow the window to be opened easily and tilted inward for cleaning. Don't worry about the condition of your windows. If your windows show an excessive amount of rot, we will repair them with epoxy consolidation and replace parts of the sash or the whole sash with matching units. Bi-Glass works on virtually any style of wood windows, including awnings, casements, picture windows, round-tops, extra-large units, and doors.

Bi-Glass Systems Can:

• Replace Your Single-Pane Glass with Double-Glazed Insulated, Low-E Glass
• Save Your Existing Sash so Your Wood Windows Retain Their Original Look
• Install a New Balance System, Jambliners Easy Tilting (Cleaning & Painting), or Invisible Spring Balances
• Add High-Grade Weatherstripping against Drafts & Insulate Weight Pockets
• Add New Cam Actuated Sash Locks
• Retain the Historical Authenticity by Retaining the Original Muntins
• Replace the Inefficient Parts of Your Window - Glass, Weatherstripping, Jambliners & Locks
• Repair Any Rotted or Damaged Wood Using Epoxy Consolidation Techniques

Bi-Glass Systems Doesn't:

• Change the Details & Look of Your Windows to a Bulky, Modern Appearance
• Change the Interior & Exterior Trim Details
• Reduce the Daylight of the Window by Adding Perimeter Spacers
• Exchange the Strong, Old-Growth Yellow Pine of Your Old Windows for the Rapid-Growth, Rot-Susceptible, New Wood of the Modern Window