Ember Proofing Your Home with Ember Resistant Vents

Ember-resistant vents help prevent windblown embers from igniting your home during a wildfire. WFCA explains their benefits and how to choose the right vents.

Disclaimer: While no home can be completely fireproof, many homeowners and citizens commonly use the term “fireproofing” when referring to fire-resistant practices. For clarity and accessibility, we have used this term throughout the article, though the more accurate term is “fire resistance.”

As wildfires become increasingly more common, new developments are being made to protect homes and property from devastation. The process of taking the necessary steps to protect your home is known as home hardening. Home hardening comes in various ways. This article delves into how you can reduce the likelihood of embers entering your home during a wildfire.

What is an Ember Resistant Vent?

Embers are small pieces of burning material that can be carried by winds up to five miles from an active fire. They are the primary cause of home loss and structural damage during wildfires, as they can ignite a new fire wherever they land.¹ Embers can also be pulled into a home through a vent or other opening.² Ember resistant vents are a crucial part of creating a fireproof home as they block the intrusion of embers and flame into spaces inside and under a structure.

How do Ember Resistant Vents Work?

Ember resistant vents, which may also be known as fire resistant vents or fire stopping vents, work by stopping embers and flames from entering an opening inside or underneath a structure.² While regular vents may have ¼” screens, ember resistant vents have 1/8” or 1/16” screens or mesh covering. The smaller openings in the vents reduce the size of particles that can filter through the vent into or under a house. They are also built with materials that have a higher level of heat and fire resistance.³

Ember Resistant Vents and Ember Resistant Mesh

A variety of ember resistant vents may be needed on a home, including under flashing vents, dormer vents, foundation vents, under eave vents, gable vents, and soffit vents. Ember resistant mesh can be used as part of these ember resistant vents, or alone as a covering for an opening. Mesh itself is less expensive than a manufactured ember resistant vent. However, vents are more likely to resist both embers and flames while mesh is adequate at resisting embers only. Mesh can also be applied over existing vents to improve their ember resistance, rather than replacing the entire vent.³

Ember Proof Vents vs Ember Resistant Vents

It is not possible for a vent to be completely ember proof, as there could be embers that are small enough to filter through a 1/8” or 1/16” opening. These are generally the smallest openings used in ember resistant vents since they still need to allow adequate airflow into and underneath structures. Ember resistant vents reduce the size and number of embers that can enter a home, but cannot be truly ember proof due to the requirement to maintain proper air circulation.³

Benefits of Installing Ember Resistant Vents

• Property owners can help to protect their home from the primary cause of structural damage during wildfires.¹ This greatly reduces the likelihood of home ignition.
• Ember resistant vents are relatively easy to install.³
• Replacing or retrofitting vents is a less expensive method of home hardening compared to replacing roofing, siding, or other larger elements of a home.

What to Look For when Shopping for Ember Resistant Vents or Retrofit Kits

When purchasing ember resistant vents or retrofit kits, homeowners should consider the design, materials used, and any standards or approvals necessary for their location.

• Design: Ember resistant vents can be constructed with a variety of elements that are designed to block embers, such as baffles, mesh, or louvers. Using multiple design elements improves the ability of a vent to prevent embers from entering.⁴ Effective vents may also use snake-like or honeycomb patterns.²
• Materials: Ember resistant vents should be made out of materials that are fire-resistant, including copper, stainless steel, galvanized steel, and intumescent coatings. Materials with less fire resistance, such as plastic, should be avoided.⁴
• Standards or approvals: Ensure that all ember resistant vents installed on your home meet any necessary requirements established by local building codes.⁴ For example, ember resistant vents are now included in Chapter7A of California’s Building Code.³  

Additional Home Hardening Strategies

In addition to ember resistant vents, many other fire-resistant materials and home hardening techniques can be applied to multiple areas in home construction, including roofing, windows, insulation, and landscaping.

• Fire resistant roofing: Utilize materials such as fiberglass-based asphalt shingles, recycled rubber tires, metal roof tiles, clay tiles, or slate when replacing a roof.⁵
• Ember resistant windows: Incorporate double-pane windows, tempered glass, and mesh screens in order to improve the ability of windows in the home to resist embers.⁶
• Fireproof insulation: Use insulation materials such as fiberglass, mineral wool, glass wool, or foam, along with a flame retardant, to increase fire resistance.^7,8
• Fire resistant landscaping: Incorporating fire-resistant plants, trees, and mulch, as well as hard-scaping features, will help to create defensible space around the home.