Single-pane windows are highly vulnerable to wildfire exposure, as they can break quickly under intense heat, allowing fire and embers to enter and ignite the interior of a building. The most effective mitigation measure is to replace single-pane windows with dual-pane windows that include at least one pane of tempered glass, which is about four times more resistant to breakage from wildfire heat compared to standard glass.

Practical Mitigation Strategies

  • Window Replacement: Upgrade to dual-pane windows with at least one pane of tempered glass. Tempered glass provides enhanced resistance to heat and impact from wind-driven embers, reducing the chance of breakage during a wildfire event.
  • Window Shutters and Barriers: Use fire-resistant shutters, plywood panels, or custom protective coverings as a temporary shield if windows cannot be immediately replaced and wildfire is imminent. Special fire-rated glass options, such as Pilkington Pyrostop, can provide rated protection but are generally more expensive and found in specialized installations.
  • Metal Mesh Screens: Installing 1/8-inch metal mesh screens over windows adds an extra layer of ember protection, preventing embers from breaking the glass or entering through openings.
  • Vegetation Management: Maintain a clear, ember-resistant zone (0–5 feet) around all windows by removing combustible vegetation and materials to minimize radiant heat exposure and direct flame contact.
  • Seal Gaps and Weather-Stripping: Use weather stripping or caulking to seal gaps around windows, which helps prevent embers and smoke from entering during a fire.
  • Close Windows During Wildfire Events: Always ensure that windows are closed during a wildfire to limit ember entry, regardless of window type or upgrades.

Temporary and Code-Driven Approaches

  • Temporary Panels: In an approaching wildfire, covering single-pane windows from the exterior with pre-cut plywood can be an emergency measure if upgrade is not possible.
  • Building Code Guidance: Most wildfire-prone regions—including areas covered by California’s Chapter 7A—now require at least one tempered pane in all dual-pane windows. Check local codes for further requirements and options for compliance.