Wildfire mitigation focuses on ember resistant vents, not ember-resistant window screens. Codes and insurance programs may require or provide credit for ember-resistant vents, while metal window screens are generally recommended as an additional home-hardening measure.

Insurance companies, inspectors, contractors, and manufacturers sometimes use words like "screens," "mesh," and "ember protection" interchangeably. However, looking at the building codes and insurance programs tells us that vents, window glazing, and window screens are treated very differently. This guide explains what may actually be required, how ember-resistant vents work, what mesh sizes appear in major standards, and where products such as EmberScreen by Phifer can fit into your fire mitigation plan.

While Vents Are Required, Window Screens Are Recommended

Wildfire codes and insurance mitigation programs address ember-resistant vents and upgraded window glazing more directly than window screens. Metal window screens can improve a home's resistance to ember and radiant heat exposure, but they are not a substitute for compliant vents or glazing.

California's 2025 Wildland-Urban Interface Code, for example, has separate provisions for vents and window glazing. Its window requirements focus on features such as multi-pane assemblies with at least one tempered pane, glass block, qualifying fire ratings, or other approved glazing. Colorado's Wildfire Resiliency Code takes a similar approach.

Insurance mitigation programs make the same distinction. California's Safer from Wildfires specifically names "Ember- and fire-resistant vents" and "Upgraded windows." The window measure is based on multi-paned glass or shutters, not insect screening.

CAL FIRE does recommend metal window screening as an additional home-hardening measure.

That is the distinction. If an insurer or inspector tells you to add ember resistant screens, clarify what they mean. In many cases, the first concern is the home's vents. Metal window screens can be a useful second layer, but they are not the same thing.

How Ember-Resistant Vents Work

So, how do ember resistant vents work? It starts by understanding the problem they are made to address. Wind-driven embers can reach a building before the main wildfire front arrives and enter attics, crawl spaces, eaves, and other concealed areas through ventilation openings.

There are two general approaches to reducing that risk.

Performance-tested vents. ASTM E2886 evaluates the ability of certain vents to resist the entry of embers and flame. The standard covers vents such as gable-end, foundation, wall-mounted, and under-eave vents.

Prescriptive metal mesh. Some codes and standards allow noncombustible, corrosion-resistant metal mesh with openings restricted to a specified size for certain vent applications.

Neither approach should be treated as a magical ember barrier. Research from the National Institute of Standards and Technology found that firebrands could continue burning against mesh until they became small enough to pass through an opening. At the same time, reducing mesh opening size greatly reduced the number of locations where ignition occurred.

That is the right way to think about ember resistant mesh or fire resistant mesh. It reduces ember penetration and can delay ignition. It does not make a building fireproof.

For homeowners sourcing material, Metro's EmberScreen Aluminum Vent Mesh is designed for vent applications. However, local code requirements vary, and mesh alone does not satisfy every vent provision in every jurisdiction. In California, for example, some ventilation openings require a State Fire Marshal-listed or ASTM E2886-tested vent assembly.

Always confirm the specific vent requirement with your local building department before installation.

What Insurance Companies Actually Ask For

Before responding to an insurer's wildfire mitigation request, separate three different concepts. A wildfire mitigation discount reduces your premium. A requirement is something your insurer may condition coverage or renewal on. Insurability is the broader question of whether a carrier is willing to write the property at all.

Home-hardening work may help with all three, but completing a particular improvement does not guarantee a discount, renewal, or new policy.

California's Safer from Wildfires Regulation

California's Safer from Wildfires regulation requires insurers to account for specified wildfire mitigation measures in their rating plans. That means qualifying mitigation must be considered for discounts. It does not mean homeowners must complete every measure in order to maintain insurance.

Under 10 CCR § 2644.9, insurers were required to submit compliant rating plans by April 12, 2023. California's Department of Insurance said in a March 2026 briefing that insurers now offer wildfire mitigation discounts ranging from 4% to 40%, although the discount available to a particular homeowner depends on the insurer and property.

For vents, the Department specifically identifies:

"Ember- and fire-resistant vents - Installing 1/16 to 1/8 inch noncombustible, corrosion-resistant metal mesh screens over exterior vents can keep wind-blown embers out of your house."

Windows are treated separately:

"Upgraded windows - Multi-paned windows are more resistant to breaking during a wildfire, which helps keep flames from entering. Multi-paned glass or added shutters all qualify."

The distinction matters. The word "screens" appears in the vent guidance because metal mesh can be installed over exterior vents. Window screens do not appear as a qualifying measure.

So California requires insurers to recognize qualifying mitigation in their rating plans. It does not require every homeowner to complete the entire mitigation list.

The California FAIR Plan Discount List

The California FAIR Plan introduced wildfire-hardening discounts on August 23, 2023. Its qualifying measures closely follow California's broader mitigation framework.

The FAIR Plan specifically names "Ember and fire-resistant vents" and "Upgraded windows," with upgraded windows described as double-paned windows or added shutters.

Again, these are two different improvements. Ember-resistant vent protection qualifies as a named wildfire-hardening measure. Window insect screens do not appear as a separate qualifying item.

If you are seeking a FAIR Plan discount, confirm the current documentation and eligibility requirements directly with the FAIR Plan before completing work.

The IBHS Wildfire Prepared Home Standard

The IBHS Wildfire Prepared Home program provides third-party verification that a home meets a defined set of wildfire-resilience measures. The program has two levels, Base and Plus, and was available in 14 states as of April 14, 2026:

• Arizona
• California
• Colorado
• Florida
• Idaho
• Montana
• Nevada
• New Mexico
• Oklahoma
• Oregon
• Texas
• Utah
• Washington
• Wyoming

The IBHS standard does not specify a 1/16-inch minimum for vents. Its prescriptive requirement sets a maximum opening of 1/8 inch.

Exterior glass appears at the Plus level and is treated as a glazing issue. The one glazed opening for which IBHS specifically requires mesh screening is an operable skylight. Those skylights must be protected with noncombustible mesh with openings no larger than 1/8 inch.

For homeowners in participating states, a Wildfire Prepared Home designation can also provide useful third-party documentation of mitigation work.

What Individual Carriers Name

Individual insurance companies may recognize different mitigation measures and discount structures. The important point is that the carrier materials reviewed for this guide repeatedly name vents and upgraded glazing, not ember-resistant window insect screens.

Horace Mann publishes particularly specific vent guidance, stating that foundation, gable, under-eave, and roof vents should be covered in 1/8-inch or 1/16-inch noncombustible, corrosion-resistant metal mesh.

That specification belongs to Horace Mann's published program. It should not be assumed to apply to every carrier.

Ember-Resistant Vent Requirements by State

There is no single national WUI code governing every home in the United States. State and local governments have adopted different wildfire construction requirements, and insurance programs create a separate layer of standards and incentives.

For vents, the major rules reviewed for this guide look like this:

California

California's wildfire construction provisions now sit under the 2025 California Wildland-Urban Interface Code, formerly CBC Chapter 7A.

Section 504.10 addresses vents. Under §504.10.1, ventilation openings generally must use vents approved and listed by the California State Fire Marshal or WUI vents tested to ASTM E2886.

A separate provision, §504.10.2, addresses certain sloped-roof vents such as dormer vents. For those applications, mesh openings must be at least 1/16 inch and no more than 1/8 inch in diameter.

This distinction is important for anyone buying loose mesh. Installing metal mesh does not automatically make every vent on a California home code compliant. Confirm the approved installation for your specific vent with the local building department.

The California WUI code also regulates glazing separately from vents. Section 504.8 addresses qualifying multi-pane glazing, tempered panes, glass block, fire-rated assemblies, and other approved window configurations.

And what about Zone 0 California? As of August 2026, the Board of Forestry's ember-resistant-zone regulations remained in draft. Zone 0 focuses on vegetation and combustible materials within the first five feet around a structure. It does not create a window-screen or vent-screening requirement.

Colorado Wildfire Resiliency Code

The Colorado Wildfire Resiliency Code creates statewide minimum wildfire-resilience standards for covered jurisdictions and construction. The state adopted the code July 1, 2025, local jurisdictions were required to adopt by April 1, 2026, and implementation began July 1, 2026.

For vents, §403.4 provides two approaches. The performance option uses listed vents tested to ASTM E2886. The prescriptive option allows "noncombustible corrosion-resistant mesh with openings not to exceed ⅛-inch."

Colorado separately regulates glazing under §404.7. Qualifying options include tempered glass, multilayered glazed panels, glass block, or assemblies with at least a 20-minute fire protection rating.

The code can also reach some work on existing structures. Triggers include replacing 25% or more of a roof surface, exterior wall work affecting 25% or more of exterior wall area, and additions increasing the building footprint by at least 500 square feet.

Colorado homeowners should also distinguish building requirements from insurance and tax rules. HB25-1182 requires additional insurer transparency around wildfire risk modeling and mitigation, but it does not mandate discounts for a specific vent or screen product.

Likewise, Colorado's current wildfire mitigation tax credit applies to vegetation and fuels work, not vents, window screens, or general structural home hardening.

For local product help, Metro also serves Colorado homeowners through our Highlands Ranch showroom.

Oregon, Washington, Utah, Montana, and Nevada

Oregon: The statewide wildfire hazard map and associated mandates created under SB 762 were repealed by SB 83 in 2025. Oregon Residential Specialty Code R327 remains a local option in communities including Ashland, Deschutes County, Grants Pass, and Sisters, with application focused on new construction. Retrofit homeowners should check locally rather than assuming a statewide requirement applies.

Washington: Washington has adopted a WUI framework, but application in high and very high hazard areas depends on statewide wildfire hazard mapping that remained under development through August 2026. The adopted 2021 Washington WUI Code uses vent mesh openings no larger than 1/4 inch. IBHS Wildfire Prepared Home became available in Washington on April 14, 2026.

Utah: Utah is phasing in local WUI code adoption. Because published sources conflict on the implementation timeline, homeowners should confirm current requirements through Utah Forestry, Fire and State Lands and their local building department.

Montana: Montana lists the 2021 International Wildland-Urban Interface Code among its adopted codes, while other guidance characterizes implementation as locally optional. For a specific project, verify which rules your jurisdiction has adopted.

Nevada: Nevada does not have a statewide WUI building code. Insurance rules are also changing, so homeowners should ask both their local building authority and insurer what applies to the property.

Texas, Arizona, New Mexico, Idaho, and Wyoming

Texas, Arizona, New Mexico, Idaho, and Wyoming do not have statewide wildfire building codes requiring ember-resistant vents across every property. Local jurisdictions can adopt their own standards.

Austin is a major example. The city adopted an amended 2024 International Wildland-Urban Interface Code effective July 10, 2025. Its vent guidance calls for noncombustible, corrosion-resistant mesh with openings no larger than 1/8 inch.

Austin also warns against ordinary window-screen material when used on vents because fiberglass material can melt. Its guidance instead directs homeowners toward galvanized or stainless-steel hardware cloth or ember-protection mesh specifically intended for WUI applications.

Arizona, Idaho, New Mexico, and Wyoming are also among the states where IBHS Wildfire Prepared Home is available, giving homeowners another pathway for third-party wildfire mitigation verification.

What Mesh Size Do You Actually Need? 1/16 Inch vs. 1/8 Inch

For most ember-resistant vent applications reviewed here, 1/8 inch is the most common maximum opening size. Some California vent applications also establish a 1/16-inch minimum. The right choice depends on your code, vent design, airflow needs, and maintenance requirements.

Why did codes move toward smaller openings? Firewise guidance warns that embers can pass through 1/4-inch mesh and ignite combustible material on the other side.

IBHS likewise advises against 1/4-inch screening over vents and identifies 1/8-inch and 1/16-inch mesh as preferable.

There is a trade-off. Fire Safe Marin reports net free areas of approximately 81% for 1/4-inch mesh, 75% for 1/8-inch mesh, and 71% for 1/16-inch mesh. Finer mesh can also collect debris more quickly and require more frequent cleaning.

CAL FIRE specifically advises homeowners to consult a building official and qualified contractor when modifying vents because added mesh or other vent treatments can reduce airflow.

For many applications, 1/8 inch represents a practical balance between ember reduction, ventilation, and cleaning burden. But do not choose a mesh size from a blog alone. Confirm the required specification for the exact vent and jurisdiction.

Metro does not publish an opening size, mesh count, or wire diameter for Phifer EmberScreen because Phifer does not currently publish those specifications. We recommend confirming the required specification before ordering rather than assuming a product meets a numerical requirement that has not been documented.

Why Fiberglass Screening Is Not an Option for Vents

Wildfire vent requirements call for noncombustible, corrosion-resistant screening materials. Ordinary fiberglass and plastic insect screening do not meet that material requirement because they can melt when exposed to heat.

Fire Safe Marin similarly advises against fiberglass or plastic mesh for ember-resistant vent applications. Austin's WUI guidance warns against ordinary window-screen material on vents and recommends galvanized or stainless-steel hardware cloth or purpose-made ember-protection mesh instead.

That is why products such as aluminum screening and stainless steel screen require different consideration from standard fiberglass insect screen.

Where Window Screens Fit Into Home Hardening

What is home hardening? It is the process of reducing the ways a wildfire can ignite or damage a building through improvements to vulnerable components such as roofs, vents, siding, decks, windows, and the immediate surroundings.

Metal window screening can play a role in home hardening or fire hardening, even though window insect screens are not a code-mandated substitute for ember-resistant vents or upgraded glazing.

CAL FIRE recommends adding screens to operable windows to help catch embers and reduce heat. It also recommends metal mesh window screens to improve window performance under radiant heat exposure.

Fire Safe Marin adds an important limitation: fine mesh can help resist ember entry, but it will not keep flames out. Wind-driven embers can still pass through screening.

That is the appropriate way to think about window screens. They are a reduction measure, not a seal and not standalone fireproofing.

There is also no ASTM, UL, or California State Fire Marshal test standard specifically for the ember resistance of window insect screening. California's WUI listing program includes categories for exterior windows and vents, but it does not contain a separate window-screen category.

For homeowners prioritizing improvements, the practical hierarchy is:

1. Address vents subject to code or insurance mitigation requirements.
2. Upgrade glazing when required or appropriate.
3. Consider metal window screens as an additional recommended layer.

Metro carries EmberScreen Stainless Steel Mesh for window and door applications. For a deeper explanation of the window side specifically, see how ember-resistant window screens protect homes.

How to Document Your Mitigation for an Insurance Credit

If you are making wildfire upgrades because of insurance, document the work before, during, and after installation. A technically correct improvement is much easier to prove when you can show exactly what was installed and where.

Keep:

• Dated before-and-after photographs of each affected vent or opening
• Itemized receipts identifying the material used
• Manufacturer product documentation
• Any available mesh specification documentation
• ASTM E2886 listing information when a tested vent assembly is installed
• Contractor invoices or installation documentation

Then ask two separate questions.

Ask your insurance carrier or agent: What documentation do you require for the discount, inspection, renewal, or mitigation credit?

Ask your local building department: What product and installation does the applicable code require for this vent?

Those questions are not interchangeable. Your insurer determines its credit or underwriting rules. Your local authority determines the building-code requirement.

Some insurers may allow homeowner documentation, while other programs rely on inspections or third-party verification. Requirements vary, so confirm the process before assuming photographs or receipts will be enough.

For homeowners in participating states, an IBHS Wildfire Prepared Home designation offers third-party verification against a standardized set of mitigation measures.

If you need to show a contractor or inspector the material you are considering, you can request a sample. For larger quantities or unusual dimensions, request a quote before ordering.

Frequently Asked Questions

Do Insurance Companies Require Ember-Resistant Screens?

Insurance wildfire programs reviewed for this guide specifically name ember-resistant vents, not ember-resistant window insect screens. Some insurers recognize qualifying vents and upgraded glazing for mitigation discounts. Metal window screens are recommended by CAL FIRE as part of home hardening, but they are not a named requirement on the programs reviewed.

How Do Ember-Resistant Vents Work?

Ember-resistant vents reduce the number and size of wind-driven embers that can enter attics, eaves, crawl spaces, and other building cavities. Protection may come from an ASTM E2886-tested vent assembly or approved noncombustible metal mesh. They reduce ember penetration but cannot guarantee that every ember will be stopped.

What Mesh Size Is Required for Ember Resistance, 1/16 Inch or 1/8 Inch?

A 1/8-inch maximum is common across major standards, including IBHS and Colorado's Wildfire Resiliency Code. Certain California sloped-roof vent applications require openings between 1/16 and 1/8 inch. Always check the code applying to your exact vent because requirements differ by location and vent type.

Does the California FAIR Plan Give a Discount for Ember-Resistant Vents?

Yes. The California FAIR Plan's wildfire-hardening discount program names "Ember and fire-resistant vents" among its qualifying measures. It separately recognizes upgraded windows such as double-paned windows or added shutters. Window insect screens are not listed as their own qualifying mitigation measure.

Is Ember-Resistant Mesh Required by California Building Code?

For certain vent applications, California allows or specifies qualifying noncombustible mesh. However, loose mesh does not satisfy every California vent requirement. The 2025 California Wildland-Urban Interface Code generally calls for State Fire Marshal-listed or ASTM E2886-tested vents, with separate mesh specifications applying to certain sloped-roof vents.

Will Metal Window Screens Lower My Homeowners Insurance?

No program reviewed for this guide names metal window insect screens as a standalone qualifying discount measure. CAL FIRE does recommend metal screens as part of home hardening, and they may contribute to an overall mitigation assessment. Ask your insurer directly before purchasing window screening specifically to obtain a premium discount.

Can I Use Fiberglass Screening on My Vents?

Ordinary fiberglass insect screening should not be used where wildfire vent standards require noncombustible screening. CAL FIRE, Fire Safe Marin, and Austin's WUI guidance warn that fiberglass or plastic screening can melt under fire exposure. Use a material and installation approved for your specific vent and local code.

What States Require Ember-Resistant Vents?

Requirements vary by state and local jurisdiction. California and Colorado have significant statewide WUI construction provisions addressing vents, while states such as Oregon, Washington, Utah, Montana, and Texas involve local adoption or implementation considerations. Arizona, New Mexico, Idaho, and Wyoming do not have statewide wildfire building codes requiring vents across every property.

Get the Right Material for the Right Opening

If an insurer or inspector tells you that your home needs "ember screens," start by asking where. Ember-resistant vents are the measure that repeatedly appears in wildfire codes, IBHS standards, and insurance mitigation programs. Metal window screens are a separate, recommended layer of home hardening.

Identify the vents on your home, confirm the applicable specification with your building department, and ask your carrier what documentation it needs before you order.

Metro Screenworks can help you source noncombustible screening materials for wildfire-hardening projects. Request a quote for your project or explore the EmberScreen by Phifer product line to compare available options.