Low-Emissivity Windows

This case study examines the role of the United States government in the development and market adoption of low-emissivity (low-e) windows. It details how federal research, computer modeling tools, standardized rating systems, and labeling programs like ENERGY STAR catalyzed private sector investment and led to widespread commercial success in building energy efficiency.

• Low-emissivity (low-e) windows significantly reduce heat loss compared to standard windows; modern double-pane low-e windows can reduce heat loss by over 70%, while the best triple-pane versions can achieve a reduction of 85%.
• The U.S. government provided critical early-stage R&D and seed funding when private firms viewed low-e technology as too risky. Between 1976 and 1983, the Department of Energy (DOE) provided $2 million (approximately $5.5 million in current dollars) to Lawrence Berkeley National Lab (LBNL) for thin film testing, prototype field testing, and energy simulations.
• The development of the WINDOW computer simulation tool by Lawrence Berkeley National Lab lowered barriers to entry by allowing the private sector to optimize designs and predict performance more cheaply and quickly. Currently, over 80% of all residential windows are modeled using these LBNL tools and certified with National Fenestration Rating Council (NFRC) ratings.
• The establishment of the National Fenestration Rating Council (NFRC) in 1989, later authorized by the Energy Policy Act of 1992, created a uniform system for testing and rating windows. This addressed consumer skepticism and manufacturer claims, providing reliable performance data that most U.S. states now require for window labeling.
• The ENERGY STAR program, which added window standards in March 1998, drove massive market adoption by helping consumers identify high-performance products. Between 2001 and 2010, the market share of ENERGY STAR windows grew from 35% to 81%, and over 98% of these energy-efficient windows utilize low-e coatings.
• Low-e windows have achieved high market penetration in the U.S., now commanding 80% of the residential window market and over 50% of the commercial window market. DOE-sponsored research from 1976-1983 resulted in net savings of more than $8 billion by the year 2000.

APA

Rissman, J., & Kennan, H. (2013). Low-Emissivity Windows. Energy Innovation. https://energyinnovation.org/wp-content/uploads/Case-Low-e-Windows.pdf

Chicago

Rissman, Jeffrey, and Hallie Kennan. Low-Emissivity Windows. Energy Innovation, 2013. https://energyinnovation.org/wp-content/uploads/Case-Low-e-Windows.pdf.

Wikipedia

{{cite report |last1=Rissman |first1=Jeffrey |last2=Kennan |first2=Hallie |title=Low-Emissivity Windows |publisher=Energy Innovation |date=March 2013 |url=https://energyinnovation.org/wp-content/uploads/Case-Low-e-Windows.pdf |access-date=17 August 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{rissman2013lowemissivity, author = {Rissman, Jeffrey and Kennan, Hallie}, title = {{Low-Emissivity Windows}}, institution = {Energy Innovation}, year = {2013}, month = mar, url = {https://energyinnovation.org/wp-content/uploads/Case-Low-e-Windows.pdf}, urldate = {2026-08-17}, note = {Indexed by Climate Insights Directory} }