Single Pane Window Retrofit System

Single Pane Window Retrofit System

OPEN 2015
Grand Rapids, Michigan
Project Term:
04/01/2016 - 03/31/2018

Critical Need:

Commercial and residential building heating, ventilation and air conditioning (HVAC) systems accounted for roughly 14% of U.S. total energy consumption in 2013. About 2.0 quads of energy are used for heat that leaks through inefficient, single-pane windows. While windows only cover 10-20% of a typical building’s walls and roof, the relative flow of energy through windows represents 60-80% of heating and cooling energy losses. Building owners often delay replacement with better double-pane windows for reasons of cost or appearance, and attractive retrofit products may not exist. Innovations to improve the cost and durability of retrofit technologies could greatly increase their adoption. If every single-panel window in the U.S. were retrofitted, the energy savings form reduced heat loss would be equivalent to the amount of electricity consumed by 32 million homes annually.

Project Innovation + Advantages:

The Mackinac Technology Company will develop an innovative, cost effective, retrofit window insulation system that will significantly reduce heat losses. The insulation system will use a durable window film that is highly transparent to visible light (more than 90% of light can pass through), but reflects thermal radiation back into the room and reduces heat loss in winter. The film will be microporous and breathable to allow air pressures to balance across the window system. The film will be bonded to a rigid frame that can be retrofitted to an existing single-pane glass window. Mackinac’s pane assembly will maintain a wrinkle-free appearance over an anticipated 20-year product lifecycle. The system will be fire resistant and lightweight (less than two pounds per square foot of window pane), which will help reduce stress on existing window panes.

Potential Impact:

If successful, Mackinac's window retrofit technology could save nearly one quad of energy if fully implemented across the U.S.


Increasing energy-efficiency is one of the easiest ways to reduce US reliance on energy imports.


The heating and cooling of buildings generates about 13% of the U.S. domestic greenhouse gas emissions. Through reduced building energy consumption, Mackinac’s retrofit system could help decrease these harmful emissions.


Mackinac’s window retrofit could be an inexpensive way to save on heating bills and improve indoor air quality and comfort.


ARPA-E Program Director:
Dr. Jennifer Gerbi
Project Contact:
John Slagter
Press and General Inquiries Email:
Project Contact Email:

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