What is the Storm Window and Insulating Panel Campaign?

The Storm Window and Insulating Panel (SWIP) Campaign is a collaborative initiative sponsored by the U.S. Department of Energy (DOE) and managed by Pacific Northwest National Laboratory (PNNL) to accelerate the adoption of low-emissivity (low-e) storm windows and insulating window panels (sometimes called window inserts or secondary glazing)—delivering  energy savings and comfort in residential and commercial buildings at a fraction of the cost of full window replacements. ​ The SWIP Campaign serves as a national platform and one-stop-shop for sharing information and recognizing successes of key stakeholders, including utilities, energy efficiency programs, weatherization organizations, home performance contractors, and others. 

SWIP Campaign Goals

  • Increase awareness, visibility, and build the body of knowledge
  • Establish a national platform for sharing information and best practices  
  • Help launch and promote new utility and energy efficiency programs  
  • Provide technical assistance and key resources  
  • Provide support to increase adoption in weatherization programs  
  • Recognize organizations that demonstrate success in adopting or promoting secondary glazing technologies 
  • Work with utilities and agencies to launch new pilot programs

Why Storm Windows?

Of the nearly 40 quads of primary energy used in residential and commercial buildings each year, just over 40% is attributed to heating and cooling buildings1. Field demonstrations have shown that the installation of low-e storm windows can reduce heating and cooling consumption by 12-33% in residential homes2. These savings are comparable to double-pane window replacement savings, but at a third of the cost. Installation is easy; in fact, an estimated 80% of storm windows are installed as a do-it-yourself measure. In addition to energy savings at a lower cost, low-e storm windows and insulating panels provide improved comfort, acoustic improvements, and aesthetic appeal. They can also be applied in historic buildings to improve window performance while preserving important aesthetic features of the primary windows. Similar benefits can be achieved in the commercial sector, where single-pane or double-pane clear glass windows are common in older buildings.  The U.S. Department of Energy estimates that if all single-pane and all double-pane clear glass windows in the U.S. were upgraded with low-e storm windows and insulating window panels, homeowners and businesses could collectively save over a quadrillion Btus of energy and $20 billion per year. 

How Storm Windows and Insulating Panels Work

Storm windows and insulating panels, typically consist of a single pane of glass or plastic in an aluminum or wood frame that is installed either on the inside or outside of the primary window. While older models needed to be installed and removed seasonally, modern storm windows are more versatile and are designed to be installed permanently. Modern storm windows are available in a variety of configurations and colors, including the option to match the function of the primary window with both fixed and operable models3.  

Storm windows and insulating panels increase the thermal performance of the primary window by creating a dead air space to reduce convective and conductive heat losses. Storm windows also increase air sealing around the window, and case studies have demonstrated an average of 10%–30% reduction in overall home air leakage4. Low-e storm windows include a pyrolytic coating which lowers the emissivity of the glass, reducing the U-factor and acting as a heat mirror. Modern storm windows now come with both an ENERGY STAR label, as well as an Attachments Energy Rating Council (AERC) energy performance rating, which includes details such as U-factor, visual transmittance, air leakage, and solar heat gain coefficient. 



  1. "Primary Energy Consumption" EIA 2019 (https://www.eia.gov/energyexplained/use-of-energy/)
  2. Katherine A. Cort, "Low-e Storm Windows: Market Assessment and Pathways to Market Transformation, "August 2013, https://doi.org/10.2172/1095439.
  3. Thomas D. Culp and Katherine A. Cort, "Energy Savings of Low-e Storm Windows and Panels across U.S. Climate Zones", January 2015, https:doi.org/10.2172/1225161.
  4. Thomas D. Culp, Sarah H. Widder, and Katherine A. Cort, "Thermal and Optical Properties of Low-e Storm Windows and Panels," 2015, https://doi.org/10.2172/1226413