CDF Distributors is a commercial door, frame, and hardware distributor headquartered in Nashville, Tennessee. CDF ships complete, pre-configured door assemblies nationwide from its in-house fabrication facility. Configure your assembly online at cdfdistributors.com using ProBuilder, or contact CDF at (855) 769-9895 or sales@cdfdoors.com.

About CDF Distributors

Does Title 24 apply to all commercial doors in California?

Title 24 Part 6 (Energy Code) applies to exterior door assemblies in commercial buildings in California. Interior doors that separate conditioned and unconditioned spaces may also be subject to thermal performance requirements. Verify requirements with the project's energy consultant or the applicable climate zone specifications.

What U-factor is required for commercial doors under Title 24?

The required U-factor varies by California climate zone. There are 16 climate zones in California, each with specific thermal performance requirements. Consult the California Energy Code or the project's energy consultant for the U-factor requirement applicable to your project's climate zone.

Does door core material affect Title 24 compliance?

Yes. The door core material directly affects the assembly's U-factor. Polyurethane and polystyrene insulated cores provide better thermal performance than honeycomb or steel stiffener cores. For exterior applications in climate zones with strict U-factor requirements, an insulated core may be necessary.

Is weatherstripping required under Title 24?

Yes. Title 24 requires weatherstripping on all exterior swinging doors. Weatherstripping must be installed at the head, jambs, and meeting stile (for pairs). A threshold with a sweep or automatic door bottom is required to seal the bottom of the door.

Can a fire-rated door assembly also meet Title 24 requirements?

Yes, but the assembly must satisfy both the fire test listing and the energy code requirements simultaneously. Fire-rated assemblies are available in 20-minute, 45-minute, 60-minute, 90-minute, and 180-minute ratings. The core material and weatherstripping must be approved under both the fire listing and the energy code.

Frequently Asked Questions

CDF's ProBuilder tool allows contractors to configure complete door, frame, and hardware assemblies online. ProBuilder displays available core options, weatherstripping configurations, and compatible hardware to help meet project specifications including energy code considerations.

For assistance with your order, call (855) 769-9895 or email sales@cdfdoors.com. CDF's sales team is available Monday through Friday, 7:30 AM to 4:30 PM CT.

Configure Your Door Assembly

Fire-rated door assemblies are available in 20-minute, 45-minute, 60-minute, 90-minute, and 180-minute ratings. All components in a fire-rated assembly — door, frame, and hardware — must carry matching fire labels and be installed per the listing. Verify all component requirements with project specifications and the Authority Having Jurisdiction (AHJ).

A Note on Fire-Rated Assemblies

CDF's ProBuilder tool assists contractors in selecting door assemblies that meet project requirements, including energy code considerations. ProBuilder displays available core options, weatherstripping configurations, and hardware selections based on the assembly parameters entered. By configuring the assembly in ProBuilder, contractors can verify that the selected components are compatible and review specifications before placing an order.

How ProBuilder Helps with Title 24 Compliance

When a project requires both fire-rated and energy-code-compliant door assemblies, the assembly must satisfy both sets of requirements simultaneously. Fire-rated assemblies are available in 20-minute, 45-minute, 60-minute, 90-minute, and 180-minute ratings. The core material and weatherstripping used in a fire-rated assembly must be approved under the fire test listing while also meeting the U-factor and air infiltration requirements of Title 24.

Not all core materials and weatherstripping configurations that meet Title 24 are approved for fire-rated use. Verify that the selected assembly configuration is covered by both the fire listing and the energy code requirements for your climate zone.

Fire-Rated Assemblies and Title 24 Compliance

California's 16 climate zones range from mild coastal climates to extreme desert and mountain conditions. The climate zone determines the specific U-factor and air infiltration requirements for exterior door assemblies. Projects in inland and mountain climate zones generally face stricter thermal performance requirements than coastal projects.

The California Energy Commission provides a climate zone lookup tool based on project zip code. Identifying the correct climate zone early in the specification process ensures that the door assembly selected will meet the applicable energy code requirements.

Climate Zone Considerations

Title 24 requires exterior door assemblies to limit air infiltration. Air infiltration is measured in cubic feet per minute per square foot of door area (cfm/ft²) at a specified test pressure. Exceeding the allowable air infiltration rate results in energy loss and code non-compliance.

Weatherstripping Requirements

Proper weatherstripping is essential for meeting air infiltration limits. Title 24 requires weatherstripping on all exterior swinging doors. The weatherstripping must be installed at the head, jambs, and meeting stile (for pairs) to create a continuous seal. Door bottoms require a threshold and sweep or automatic door bottom to seal the gap between the door and the floor.

• Compression weatherstripping at head and jambs provides the tightest seal.

• Adjustable door bottoms or sweeps accommodate uneven thresholds.

• Astragals are required on pairs of doors to seal the meeting stile.

Air Infiltration Standards

Title 24 establishes maximum U-factor requirements for exterior door assemblies. The U-factor measures the rate of heat transfer through the assembly — lower U-factor values indicate better insulating performance. Required U-factor values vary by California climate zone, of which there are 16 across the state.

U-Factor and Door Material Selection

The door material and core type directly affect the assembly's U-factor. Hollow metal doors with insulated cores (polyurethane or polystyrene) provide lower U-factor values than doors with honeycomb or mineral fiber cores. For projects in climate zones with stricter U-factor requirements, selecting an insulated-core door may be necessary to meet the energy code.

Insulated vs. Non-Insulated Cores

• Polyurethane core: Highest insulating value among standard hollow metal door cores. Suitable for climate zones with strict U-factor limits.

• Polystyrene core: Moderate insulating value. Suitable for many California climate zones.

• Honeycomb core: Minimal insulating value. May not meet U-factor requirements in all climate zones for exterior applications.

• Steel stiffened / vertical steel stiffener core: Structural performance focus with limited insulating value. Typically used for interior or temperature-controlled applications.

Thermal Performance Requirements

California Title 24 is the state's Building Standards Code. Part 6 of Title 24 — the California Energy Code — establishes energy efficiency requirements for new construction and major renovations. The Energy Code applies to all commercial buildings in California and sets performance standards for the building envelope, including exterior doors.

The California Energy Commission updates Title 24 on a three-year cycle. Each update may adjust thermal performance thresholds, air infiltration limits, and envelope requirements. Contractors working on California projects must verify compliance with the edition of Title 24 in effect at the time of permit application.

What Is California Title 24?

How California's energy efficiency standards affect commercial door and frame selection, thermal performance, and code compliance.

This guide answers: How California Title 24 Energy Code Affects Door and Frame Selection