In “Mind the Gap: Summary of Window Residential Retrofit Solutions,” researchers explore window retrofit options that have the potential to improve a home’s energy performance and general comfort. The study’s abstract reads:

“Improving the insulation, solar heat gain, and infiltration characteristics of windows in a home has the potential to significantly improve the overall thermal performance by reducing heat transfer through the window and also by decreasing air leakage into and out of the home. As approximately 43% of existing homes still have low-performing, single-pane clear windows (~50 million houses) and millions of other homes have only double-pane clear glass windows (Cort 2013), improving window performance also presents a significant opportunity for energy savings in the residential sector. Today, various energy-saving window retrofit opportunities are available to homeowners, ranging from window coverings and storm panels to highly-insulating triple-pane R-5 window replacements. Many of these technologies have been evaluated in the field, in the Lab Homes at Pacific Northwest National Laboratory (PNNL), and through modeling to prove their cost-effectiveness and performance in different climate regions. Such information is necessary to increase market penetration of such efficient technologies. Recently, the Pacific Northwest’s Regional Technical Forum approved a utility measure for low- emissivity storm windows based on such data. This action represents a watershed moment for increasing the variety and prevalence of fenestration options in utility programs, especially for the low-income demographic. This paper will review various window retrofit options, the most recent field test and modeling data regarding their performance and cost-effectiveness, and discuss future rating efforts. This information is useful for utilities and energy-efficiency program managers to help effectively implement incentive measures for these technologies.”

For the full study, please see our Reports page.

The study has also been highlighted in the most recent edition of Home Energy Performance Magazine!