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Everything You Need to Pass Title 24 — First Time, Every Time

Compliance checklists, leakage rate requirements, climate zone R-values, and exemptions — all in one place. Submit jobs online and we handle the rest.

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When is a Title 24 Verification & Permit Required?

A permit and Title 24 verification are required any time an HVAC system is replaced or altered in California — regardless of system size, age of the home, or whether the homeowner requests it.

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Condenser / AC Unit Replacement

Replacing an outdoor condensing unit or air conditioner requires a permit and Title 24 verification in all California climate zones. Duct leakage testing is required by the city or county building department.

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Furnace / FAU Replacement

Replacing a gas furnace or forced air unit triggers Title 24 compliance. A permit must be pulled before work begins and a Title 24 verification inspection must be completed before final sign-off.

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Ductwork Replacement or Alteration

Any replacement or alteration of ductwork requires a permit and duct leakage testing. The standard that applies (5% or 10%) depends on how much of the duct system is being replaced.

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Heat Pump Installation or Replacement

Heat pump installations and replacements require Title 24 verification. Note: under the 2025 California Energy Code, some single-family AC replacements may now require upgrading to a heat pump system.

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New Construction

All new construction requires Title 24 compliance including HVAC verification, duct leakage testing, and load calculations to ensure the system is properly sized for the building.

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Any Alteration to Existing System

Any alteration, relocation, or reconstruction of an existing mechanical system requires a permit prior to work beginning per the California Mechanical Code.

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No Exceptions by System Size or Age

A written construction permit must be obtained prior to the erection, construction, reconstruction, installation, relocation, or alteration of any mechanical system in California. If work is being done, a permit is required.

Title 24 Compliance Checklist

The items below are California Title 24 state energy compliance requirements — what TopNotch Energy Compliance Services inspects and certifies. City and building department requirements are listed separately below.

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Changeout / Less Than 75% Duct Replaced

Standard
Duct leakage rate ≤ 10% of total system airflowTested at 25 pascals. Accessible leakage only.
Minimum airflow 300 CFM per tonMeasured at the air handler
Duct insulation on new duct portions R-6 or R-8 depending on climate zoneSee climate zone table below
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75% or More Duct Replaced / New System

Stricter
Duct leakage rate ≤ 5% of total system airflowTested at 25 pascals. System treated as entirely new.
Minimum airflow 350 CFM per tonHigher standard applies to new/major duct replacement
Fan watt efficacy Must meet Title 24 fan efficiency requirementsRequired for 75%+ duct replacement jobs
Duct insulation on all duct portions R-6 or R-8 depending on climate zoneSee climate zone table below
Duct Leakage Testing — Exceptions & Exemptions
  • Asbestos present in existing ductwork — testing is exempt for safety reasons
  • Inaccessible leakage does not cause failures — only accessible duct leakage is tested using the smoke test method
  • System has already had a prior Title 24 inspection — does not require duct leakage testing again
  • Less than 25 feet of ductwork — systems with less than 25 linear feet of ductwork are exempt from duct leakage testing

R-Value Requirements by Climate Zone

California Title 24 requires specific R-values for new portions of supply-air and return-air ducts or plenums. Requirements vary by climate zone.

Climate Zone(s)Required R-ValueApplies ToExample Areas
CZ 3, 5, 6, 7 R-6 New portions of supply-air and return-air ducts or plenums Parts of Bay Area, Central Coast, San Diego coastal areas
CZ 1, 2, 4, 8, 9, 10, 11, 12, 13, 14, 15, 16 R-8 New portions of supply-air and return-air ducts or plenums Inland Empire, Los Angeles, Sacramento Valley, Desert regions, High Desert
Not sure which climate zone your job site is in? Look it up using the CEC Climate Zone map at energy.ca.gov — or contact us and we'll confirm it for you before your inspection.

Leakage Rate & Airflow Requirements

Leakage is tested at 25 pascals pressure. Only accessible duct leakage is measured. Results are expressed as a percentage of total system airflow.

ScenarioMax Leakage RateMin AirflowAdditional Requirements
Changeout / Less than 75% of ducts replaced ≤ 10% of total system airflowTested at 25 pascals 300 CFM per ton Standard city requirements apply
75% or more of ducts replaced
Treated as entirely new system
≤ 5% of total system airflowTested at 25 pascals — stricter standard 350 CFM per ton Fan watt efficacy required + all city requirements
Asbestos present Exempt N/A Document asbestos presence on compliance form
Inaccessible Leakage Does not cause failure N/A Only accessible leakage tested via smoke test. Document inaccessibility.
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Separate from Title 24

The items below are local city and building department requirements — they are enforced by the city inspector during the permit inspection, not by Title 24 Verification. These vary by jurisdiction so always confirm with your local building department.

What the City Inspector Checks

These requirements are enforced by your local city or building department inspector — separate from Title 24. They vary by jurisdiction so always verify before installation.

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Condenser Setback Distance

Minimum required distance from the condenser unit to the structure. Varies by city — confirm before installation.

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UV Wrapped Refrigerant Lines

UV-resistant insulation wrap required on all exposed outdoor refrigerant lines to protect against sun degradation.

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Locking Refrigerant Caps

Locking caps must be installed on all refrigerant service ports to prevent tampering and unauthorized access.

Correct Fuse/Breaker Size

Fuse or breaker size must match the manufacturer's specification on the equipment nameplate exactly.

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Condensation Drainage

Condensate drain lines must be properly sloped and verified to be draining correctly.

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Permit & Inspection Card

The permit must be pulled and posted at the job site before work begins. The inspection card must be signed off by the city inspector.

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