Do I need a Title 24 report to replace my windows?

Window replacement is an alteration to the building envelope, so the Energy Code applies. For alterations that need no field verification, window replacements among them, the building department may choose not to require a certificate of compliance, or may accept a simplified form. Ask your department what it wants for your scope.

Who hires the ECC-Rater?

The builder or the building owner. On an HVAC changeout, the installing contractor may hire the ECC-Rater only if the homeowner authorises it. The rater must be independent of the builder or general contractor.

Is a Title 24 report the same as a HERS rating?

No. Since 1 January 2026, field verification for Energy Code compliance sits in the Energy Code Compliance (ECC) Program. What remains in the HERS Program is the whole-house rating program, which is separate from showing Title 24 compliance.

Which documents should I keep when the job is finished?

The CF1R, the CF2Rs from each installer and, where testing was required, the CF3Rs from the ECC-Rater, plus the builder's manual on operating and maintaining the home's energy features. The builder is required to leave these in the building at occupancy.

What Every California Homeowner Should Know About Title 24

What the Energy Code asks of a homeowner, from the first drawing to final inspection: which projects it covers, who produces each document, when the ECC-Rater visits, and the surprises that most often cost people time.

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Most homeowners meet Title 24 as a line on a permit checklist. You do not have to master it. It does help to know what it asks for, who produces each piece of paperwork, and where projects tend to lose time, because the decisions that affect it are made by you and your designer long before anyone opens the energy software. For a short overview of the service itself, see Title 24 reports for homeowners.

What Title 24 is, in plain terms

Title 24 is California's building standards code, and Part 6 of it is the Energy Code. It sets minimum energy requirements for the building envelope, heating and cooling, water heating, ventilation and lighting, and for new homes it includes solar. The California Energy Commission adopts it and updates it every three years. Your local building department enforces it, first at plan check and then at inspection. The 2025 edition governs any permit application submitted on or after 1 January 2026. There is a longer explanation in What is Title 24?, and the requirements themselves are summarised in Title 24 requirements.

Which home projects bring it in

The Energy Code applies to new buildings, additions and alterations. It does not apply to repairs, meaning reconstruction or renewal for maintenance. Replacing a component the code regulates, such as a roof covering or a water heater, counts as an alteration rather than a repair.

New homes and new detached ADUs are newly constructed buildings and meet the full new-construction requirements, including solar unless an exception applies.
Additions increase conditioned floor area and volume. That includes converting a garage into living space, enclosing and conditioning a patio, and legalising a conditioned room that was added without a permit.
Alterations change the envelope, heating, cooling, water heating or hardwired lighting of existing space: new windows, a heat pump, a replacement water heater, added insulation, a new roof over conditioned space, or extended ductwork.
Repairs and cosmetic work such as paint, flooring and cabinets do not change a regulated system, so they do not bring in the Energy Code.

Small jobs have some flexibility. For alterations that need no field verification, including water heater and window replacements, and for additions under 300 square feet that need none, the building department may decide not to require a certificate of compliance, or may use a simplified form. That is the department's decision, so ask before paying for a report. Do I need a Title 24 report? goes through the common cases.

Who does what

Three documents carry a residential project, and each belongs to a different person.

The CF1R, certificate of compliance. Prepared at design stage, often by an energy consultant, and signed by the consultant as documentation author and by the person responsible for the design. It goes in with the permit application, and the plan checker compares it with your drawings.
The CF2R, certificate of installation. Completed during construction by the contractors who install the windows, insulation, ducts, equipment and lighting, confirming that what they installed matches the approved plans.
The CF3R, certificate of verification. Completed by an ECC-Rater after field verification and diagnostic testing, where the project requires it.

Where field verification is required, all three are registered with an ECC-Provider data registry such as CHEERS, and each document receives a registration number. At the end of the job the builder must leave the completed documents in the home, along with a manual on operating and maintaining its energy features. Keep them with the house records.

The ECC field visits

An ECC-Rater is an independent, third-party verifier certified by an ECC-Provider that the Energy Commission has approved. The role was called a HERS rater until 1 January 2026, when field verification and diagnostic testing moved into the Energy Code Compliance (ECC) Program. The CF1R lists which items your house needs. On a new home with central heating and cooling, duct sealing, system airflow, fan watt draw and the ventilation fans are verified; other common items include refrigerant charge, quality insulation installation and higher-than-minimum equipment ratings.

Three practical points. The builder or the owner hires the ECC-Rater, and on an HVAC changeout the installing contractor may hire one only if you authorise it. The rater must be independent of the builder. And if a test fails, the installer corrects the work and the rater retests; the failure is recorded in the registry, and at final inspection the inspector checks that the required CF2R and CF3R forms are complete, signed and registered. Read more in What is an ECC-Rater?

Timing, from your side

The report belongs at design stage, once the floor plan, windows and equipment are settled enough to model but before the permit set is final. Its results can feed back into the design: a window package or equipment choice sometimes has to change to comply, and that is cheap on paper and expensive after ordering.

The code edition is fixed by your permit application date, not by when construction starts. One catch: if a permit lapses before any work is done and you apply again, the new application is checked against whichever code is current by then.

During construction, the building inspector typically visits at the foundation, framing, insulation, drywall and final stages, though the sequence varies by jurisdiction. Installed insulation is checked against the CF1R before the drywall goes up, so a crew that installs a different product can mean opening walls. ECC testing happens once the systems are in, and it has to be booked, so leave room for it before the final inspection.

The surprises that cost homeowners time

A like-for-like HVAC swap is not exempt. Replacing an air handler, an outdoor unit, a coil or a whole packaged system triggers sealing and ECC testing of the connected ducts. Replacing only the outdoor unit counts. There are narrow exceptions, such as duct systems with less than 40 feet of duct.
Heat pumps are the baseline for new homes. The 2025 prescriptive requirements for newly constructed single-family homes include a heat pump for space heating, in all 16 climate zones. A gas furnace raises the modelled heating energy significantly, so it has to be offset by better performance elsewhere.
A new detached ADU usually needs solar. It is new construction, so the solar requirement applies unless an exception does. The Energy Commission lets you meet it by adding new modules to an existing solar system on the main house, as long as they are included in the ADU permit. A garage conversion, or an ADU built within existing space, is not subject to that requirement.
Unknown existing construction. Where nobody knows what is inside the walls of an older house, default values based on the year it was built can be used. An ECC-Rater can verify the existing conditions instead, and verified values change the baseline the alteration is measured against, which can work in your favour.
Substitutions on site. A different window, heat pump or insulation product from the one on the CF1R means the documents no longer describe the house. When a change on site affects compliance, the building department has to approve revised plans and revised energy documents.

How to avoid delays

Ask the building department early whether your scope needs a report, and how it wants the CF1R submitted: printed on the plan sheets, or attached.
Settle the windows and the heating, cooling and water heating equipment before the report, and put the same values on the drawings.
Give the full street address. California has 16 climate zones, and their boundaries do not always follow ZIP codes.
Read the special features and ECC lists on the CF1R, and pass them to your contractor before work starts. The guide to reading your CF1R shows where they are.
Book the ECC-Rater when the HVAC installation is scheduled, not after.
Tell your energy consultant about any change before it is built.

Before ordering, the Title 24 checklist lists what to gather, and 15 Title 24 mistakes covers what plan checkers commonly send back.

Title24.Pro prepares residential and ADU reports 100% online: you upload PDF plans, and a permit-ready PDF arrives by email, with CHEERS registration where your project requires it.