Open Sash

Energy Retrofit for Old Windows

restoration of old windowOpen Sash specializes in energy efficiency, weatherization, and restoration of old windows.

An Open Sash energy retrofit turns beautiful quality-made old windows into ones that are as energy efficient as a modern window—at a price that is lower than replacements.

Open Sash has developed a unique system for adding glass to the existing sash that doubles the thermal resistance of the window without changing the look or function. With the addition of modern integrated weather seals, foam insulated weight cavities, and restoration treatment, your old windows will look great and function as well as a modern window.

Our retrofit system can be used on any type of window – from historic to factory modern, single or double hung, casement or fixed. Our energy panels are custom-made to fit your needs.

In addition to being affordable, our window retrofits are also the most earth friendly, carbon neutral, and sustainable choice you can make.

Learn More About the Open Sash System

Latest News from Open Sash

Open Sash repairs and retrofits modern windows too.

Posted May 29th, 2017 by Chris Pratt

There are many houses built in the 70’s and 80’s that have casement windows with insulated glass.  Many of the Andersen, Pella and Marvin windows have  serios wear on the exterior,  broken cranks and keepers , worn seals  and  fogged  insulated glass.   If the  wooden sash and the frames are good,  then Open Sash can retrofit them very cost effectively.

Removing the old window and replacing it with an entirely new unit is expensive for three reasons.  1) The unit itself is expensive,  2) It takes a lot of time and money to remove it and dispose of it, and 3)  It takes a lot of time to install the new unit because it involves fitting into the existing exterior and interior trim.   The entire cost /window could be between $1,000-$3,000.00.

An open sash retrofit can be done for  $250–$500, depending on size and how many elements of  the window need to be replaced.  The addition of a frame to the exterior and a low-energy panel gives new life to the outside and adds another layer of glass for triple pane insulation.

Casement windows after EP and Frames

Casement windows after the addition of the frame and the low-energy panel.

Here is an example of house we did in East Montpelier, VT that made the window look new and will  give them another 15-20 years of life, which about what you can expect from a new window.

Casement Before with Worn wooden frames with degraded glazing

Casement Before with Worn wooden frames with degraded glazing




Open Sash Exhibits at Waterbury LEAP Energy Fair

Posted April 25th, 2017 by Chris Pratt

Chris Pratt demonstrating to LEAP energy fair attendees the Open Sash window retrofit system.

Chris Pratt demonstrating to LEAP energy fair attendees the Open Sash window retrofit system.


Chris Pratt and Troy Borland demonstrating Open Sash window system to attendees of LEAP Energy Fair.

Chris Pratt explains the Open Sash system to attendees of the LEAP Energy Fair in Waterbury,Vermont.