When Is Title 24 Required? California Project Triggers

You need a Title 24 report when your project builds new conditioned space or changes something the Energy Code regulates: the building shell, heating, cooling, water heating or lighting. Repairs are not covered, and some small alterations only need to meet a few mandatory rules.

The Energy Code sorts every project into one of four kinds. Find yours below.

The four kinds of project

Kind	What it means	Examples
New construction	A new building	New home, new detached ADU
Addition	Adds conditioned floor area and volume	Room addition, attached ADU, garage conversion, enclosing a patio
Alteration	Changes the envelope, HVAC, water heating or lighting, without adding conditioned space	New windows, HVAC changeout, water heater replacement, reroof, adding insulation
Repair	Restores something to its original condition	Replacing broken glass in an existing frame

New construction and additions always need a CF1R. Alterations need one when the work touches a regulated feature. Repairs do not.

New homes and detached ADUs

A new home needs a full Title 24 report, almost always done with the performance method. A new detached ADU is treated the same way as a new home, which usually means solar PV too. See Title 24 for new homes and Title 24 for ADUs.

Additions, attached ADUs and garage conversions

The CEC defines an addition as any change that increases both conditioned floor area and conditioned volume. Its 2025 manual gives these examples:

Adding a conditioned sunroom or other living space.
Converting a garage or other unheated space into living space.
Enclosing and conditioning an existing patio.
Legalizing a conditioned space that was added without a permit.
Adding a floor-to-ceiling bay window that adds floor area and volume.

Adding a loft inside an existing vaulted room adds floor area but not volume, so the CEC treats it as an alteration. Our guides to home additions and garage conversions cover the size-based rules.

Alterations: which ones trigger the Energy Code

Here is how the 2025 code treats the most common home alterations. "Prescriptive" means the rule your project meets if you do not model the whole house.

Alteration	What the 2025 code requires (prescriptive)	ECC testing likely?
Replacing windows	U-factor and SHGC limits for your climate zone, with a small-area exception	No
Adding window area	Window area, west-facing area, U-factor and SHGC limits	No
Replacing a complete HVAC system	Load-based sizing, thermostat, duct, airflow and refrigerant charge rules	Yes
Replacing an air conditioner, heat pump, furnace coil or air handler	Duct sealing, setback thermostat, refrigerant charge checks where they apply	Yes
Adding or replacing more than 25 feet of ducts	Duct insulation and duct sealing	Yes
Replacing a water heater	Pick from the allowed list (see below), plus pipe insulation	No
Replacing more than half of a roof	Cool roof product in certain climate zones, unless exempt	No
Adding new hardwired lighting	Lighting efficacy and controls	No

Replacing windows

New windows that replace old ones of the same total area must meet the U-factor and SHGC values for your climate zone. Small jobs get an exception: up to 75 square feet of replacement windows may have a U-factor up to 0.40, and an SHGC up to 0.35 in climate zones 2, 4 and 6 through 15. Replaced skylights may have a U-factor up to 0.40 and an SHGC up to 0.30.

Replacing only the glass in an existing sash and frame is a repair, not an alteration. Our window replacement guide has the full table by climate zone.

Replacing heating or air conditioning

An HVAC changeout is one of the most common alterations, and it usually needs ECC (HERS) testing. The CEC's manual says HVAC changeouts use the CF1R-ALT-02 form under the prescriptive path.

What the 2025 code asks for when you replace equipment:

Duct sealing. When you replace the air handler, outdoor unit or coil, the connected ducts must be sealed and tested by an ECC-Rater. Exceptions include duct systems under 40 linear feet, ducts already sealed and verified, and ducts with asbestos.
Setback thermostat. When refrigerant parts are replaced, every thermostat on the system must be a setback thermostat.
Refrigerant charge and airflow. Required for heat pumps in all climate zones and for air conditioners in climate zones 2 and 8 through 15, with exceptions.
No new electric resistance heat as the main heat source, unless the home already uses electric resistance heat and an exception applies.

The CEC allows an exception for urgent changeouts. The certificates can be registered after the work, as long as it happens before the permit is closed.

Replacing a water heater

A replacement water heater must be one of these, under Section 150.2(b)1H:

A natural gas or propane water heater.
A heat pump water heater installed indoors on an insulated base of at least R-10, with a demand-response communication port.
A heat pump water heater that meets the NEEA Advanced Water Heater Specification Tier 3 or higher.
If the old water heater is electric resistance, a new consumer electric water heater.

Accessible hot water piping must be insulated. If you add a recirculation loop, it must be a demand system with a manual on/off control.

Reroofing

When more than half of the roof is replaced, the new roofing must meet the cool roof rules in certain climate zones. For steep-sloped roofs (most homes), that means climate zones 4 and 8 through 15. The product needs a minimum aged solar reflectance of 0.20 and thermal emittance of 0.75, or an SRI of 16.

You are exempt if any of these is true:

The ceiling has at least R-38 insulation.
The attic has a radiant barrier that meets the code.
There are no ducts in the attic, in climate zones 2, 4, 9, 10, 12 and 14.
There is R-2 or more of continuous insulation above or below the roof deck.

Remodels with only small changes

The CEC's manual gives an example: a remodel that only adds new faucets and bathroom lighting is still an alteration, but it only has to meet the mandatory rules for appliances and residential lighting. A small scope can still be covered, even if no full report is needed. Ask your building department what it wants submitted.

Who decides?

Your building department. It enforces the Energy Code and sets its own submittal rules. Some cities also adopt local energy ordinances that go further than the state code, and the CEC keeps a list of them.

Not sure which kind your project is? Start with our complete Title 24 guide.

Ready to order? See our flat prices.

Frequently asked questions

Does replacing my air conditioner need a Title 24 report?

Usually yes. A space conditioning changeout is an alteration, and the CEC's compliance manual says HVAC changeouts use a CF1R-ALT-02 form when complying prescriptively. Most changeouts also need ECC (HERS) testing, such as duct leakage.

Can I register the HVAC changeout paperwork after the work is done?

The CEC allows an exception for urgent alterations such as HVAC changeouts: the certificates can be registered later, but before the permit is closed or finalized.

Do I need Title 24 to replace a gas water heater?

The replacement is an alteration, so it must meet the Energy Code. Under Section 150.2(b)1H, a new natural gas or propane water heater is one of the allowed choices. Ask your building department which form it wants with the permit.

Does a new roof trigger Title 24?

Replacing more than half of the roof surface triggers cool roof rules in certain climate zones. For steep-sloped roofs, those zones are 4 and 8 through 15, and there are several ways to be exempt, such as R-38 ceiling insulation or an attic radiant barrier.

Is a repair covered by Title 24?

No. The CEC's 2025 compliance manual says the Energy Code does not apply to repairs. Replacing glass in an existing sash and frame counts as a repair if the new glass performs at least as well.

Who decides whether my project needs a Title 24 report?

Your local building department. The Energy Code is statewide, but each department sets its own submittal requirements, and some cities add stricter local energy ordinances.

When is a Title 24 report required?