Two individuals install a secondary glazing system window on top of an existing commercial window.

Illustration of an energy-efficient secondary glazing system being installed in a commercial building with minimal disruption

Graphic by Al Hicks, NREL

The U.S. Department of Energy (DOE) has launched the American-Made Building Envelope Innovation Prize—Secondary Glazing Systems, which will offer up to $2 million to encourage production of high-performance, cost-effective secondary glazing systems to improve efficiency of commercial windows. 

Sponsored by DOE’s Building Technologies Office (BTO), the inaugural Building Envelope Innovation Prize targets novel solutions for commercial window upgrades to enable equitable decarbonization and optimize building envelopes for electrification. Secondary glazing involves installing an additional windowpane on an existing window to improve insulation.

Register for an informational webinar on February 27 at 11 a.m. ET to learn more about this prize and the official rules

“About 40% of U.S. commercial buildings, including multifamily residences, have single-pane windows, which are uncomfortable for occupants and waste energy,” Jeff Marootian, Principal Deputy Assistant Secretary for Energy Efficiency and Renewable Energy, said. “Yet less than 1% of commercial buildings get full window replacements each year because it is so expensive and disruptive for occupants. Secondary glazing systems can help solve this problem.”

 Secondary glazing systems currently on the market can improve energy efficiency without needing to remove existing windows, but the potential of this technology has not been fully realized. The goal of this prize is to spur development of next-generation secondary windows that increase building resilience and comfort and decrease energy consumption—all while being highly cost-effective. 

“While secondary glazing systems currently exist, they are a small portion of the market and are not widely adopted, despite costing markedly less than a full window replacement,” Marc LaFrance, Windows Technology Manager for DOE’s Building Technologies Office, said. “This prize will improve equitable access to efficient retrofit technologies by reducing product and installation costs.”

Improved window energy efficiency will lead to more attainable building electrification, as smaller heat pumps will be able to serve the building’s reduced energy needs. The Building Envelope Innovation Prize aims to fund development of promising, cost-effective, market-ready secondary glazing system solutions across three phases:

Building Envelope Prize Timeline
  • Phase 1: Design Concept—$50,000 | February 14 to June 13, 2024
    • Teams will provide an innovative concept narrative and design drawings for a secondary glazing system prototype, including details on cost and energy performance.
    • Up to five semifinalists will be selected, each receiving $50,000.
    • Phase 1 awards will be based on energy and technical performance modeling, cost metrics, and construction plans.
    • Teams can only join during Phase 1
  • Phase 2: Prototype—$200,000 | September 2024 to March 2025
    • Semifinalist teams selected from Phase 1 will submit a secondary glazing system prototype and technical narrative as well as secure an equity-focused pilot demonstration partner.
    • Phase 2 focus areas will include market readiness, cost-effectiveness, and the ability to be deployed.
    • Up to three finalists will be selected, each receiving $200,000.
    • Phase 2 awards will be based on prototype construction, as well as thermal and optical performance tests run by a national laboratory.
  • Phase 3: Commercialization—$750,000 | May 2025 to May 2026
    • Finalist teams selected from Phase 2 will work with their equity-focused pilot demonstration partners and submit plans for commercialization. 
    • Phase 3 will focus on commercial viability—including price point, ease of installation, etc.
    • Up to two winners will be selected. First place will receive $750,000; second place will receive $400,000.
    • Phase 3 awards will be based on prototype durability testing results, rigor of commercialization plans, and implementation of equity-focused pilot demonstrations in low-income multifamily or underserved public sector buildings.

The Design Concept phase will accept applications of innovative secondary glazing system designs through June 13, 2024. All interested applicants must join by that date; Phase 2 and Phase 3 will not accept new competitors.