Rebuilding Brings Fire-Resistant Doors and Windows Into Focus

Amid the Los Angeles wildfires in 2025, Ardie Tavangarian’s family lost their home in Pacific Palisades, along with most of their belongings, he told the Wall Street Journal. “My peace of mind was basically pulled from under my feet,” he told writer Katherine Clarke.

Tavangarian has since rebuilt, the article explains, this time with “an extremely fire-resistant home to serve as a model for rebuilding.”

According to the article, the new home’s exterior walls can withstand an active blaze for six hours. The windows contain borosilicate glass—the type typically used in laboratory equipment and cookware. They cost $300,000 for the roughly 4,200-square-foot structure, the article reports.

With rebuilding efforts has come a new level of interest among homeowners, builders and developers in fire-resistant materials and features—including doors and windows. As a result, interest in fire-rated entry doors is growing, said Katie Hren, product designer for Novatech.

“Usually [it was] just the garage door between your house and the garage that was always mandatory,” Hren said. “But I think it’s become more of a want and a need.”

In response, Novatech is just one manufacturer that has expanded its offerings to include more fire-rated doors—now across all embossment styles, she said. Previously the company only offered 20-minute fire-rated options in a six-panel configuration. None of those doors include glass, but other manufacturers have such options, including TruStile and MMI Door.

How Windows Fair

It is important to understand the risk fire poses to doors and windows to further develop research and materials to ensure they provide added protection, Gavin Horn of UL’s Fire Safety Research Institute (FSRI), told attendees at the Fenestration and Glazing Industry Alliance’s (FGIA) recent Annual Conference.

Daniel Gorham, also with FSRI, said there are multiple preventative measures that can mitigate fire damage, such as installing dual- or multi-pane windows with at least one lite of tempered glass. These windows will help hold off flames long enough for an occupant to escape.

Joseph Willi noted that FSRI has conducted multiple structure-to-structure experiments to test the efficacy of materials ranging from window lite assemblies to siding. The experiments studied four types of double-pane window assemblies, including both lites annealed, both lites tempered, fire-side annealed, back-side tempered, and fire-side tempered, back-side annealed.

Eight experiments were conducted with a 10-foot separation between custom-built, solid-framed structures. FSRI also conducted one-off experiments with different separation distances and rotated the windows, defining failures as the first instance of cracking.

Willi said FSRI found that the fire-side lite failed no matter the assembly. However, annealed fire side, tempered back side outperformed windows with the opposite configuration. Window lite assemblies with both lites of tempered glass performed the best of the four types.

At the same time, heat transfer through windows has the potential to ignite interior combustibles even without window failure, Willi pointed out.

FSRI also looked at window frames, including vinyl, wood, fiberglass and aluminum. All the lites in the windows were double-lite tempered glass. For front-side fires, unsurprisingly, wood was the first to ignite. Aluminum and aluminum cladding had the fewest instances of ignition; however, it was dependent on whether the cladding stayed attached to the window frame.

Overall, vinyl and wood frames were most vulnerable to sash failure, he said, while fiberglass had the fewest instances, followed by aluminum.

When it comes to fire resistance, there is no perfect material, testing showed. Aluminum frames were the top performer, but still vulnerable due to secondary components.

In the end, “A home’s overall fire resilience is only as strong as its weakest link,” researchers for the Insurance Institute for Business & Home Safety (IBHS) said in 2025 report. But “a combination of noncombustible building materials and double-pane tempered windows in a resilient frame—such as fiberglass or metal—significantly reduces the likelihood of total loss,” they added.