01Key facts / TL;DR
It depends on the building and permit scope: installing storage is not automatically an order for a full energy model.
No, battery-ready infrastructure is not the same as an installed battery or a guaranteed backup system.
Yes, the 2025 Energy Code has mandatory BESS-ready provisions for qualifying newly constructed single-family buildings, with conditions and exceptions.
No, the CEC does not extend those single-family BESS-ready provisions to additions and alterations; other applicable requirements still need review.
Battery readiness
Part 6 energy documents are a separate track
Title 24 Part 6 energy documents are different from electrical approvals and from CALGreen (Part 11) readiness requirements. Each is reviewed on its own terms.
Battery readiness, and any Part 6 requirements that apply to your project, do not replace electrical, fire or other applicable reviews. Not every existing battery installation needs a CF1R; scope and classification decide.
What Title 24 Lab prepares
Design-phase Part 6 energy documents, not CALGreen documentation. Energy reports do not replace electrical plans or fire review submittals.
Educational information, not legal advice or a compliance determination. Confirm requirements and the applicable code cycle for your permit application date with your building department (AHJ).
02Three questions that often get confused
First, is a battery actually being installed, or is a new building being prepared for a future battery? Second, does a larger building project already require energy compliance documentation? Third, which electrical, building, fire-safety or utility approvals apply to the proposed installation? These are related questions, not interchangeable certificates.
A stationary battery energy storage system, or BESS, stores electricity for later use. A battery-ready building has specified provisions for future connection. Neither term alone tells you that an existing house needs a new whole-building performance model.
Start by defining standalone storage, a PV-plus-storage installation, a new dwelling or a broader alteration. Ask the AHJ which documents belong to that exact permit. An energy report does not itself approve electrical connections, establish safe battery placement or authorize utility operation.
03What the CEC says about single-family BESS readiness
The CEC’s 2025 single-family BESS-ready FAQs explain Section 150.0(s): newly constructed single-family buildings with one or two dwelling units and utility-provided dwelling electrical service greater than 125 amps are subject to the stated readiness requirements. The source identifies conditions, configurations and an exception for buildings with BESS installed.
Importantly, that CEC FAQ explicitly says these BESS-ready requirements do not apply to additions or alterations. Do not turn “some building work is happening” into a universal requirement to add battery-ready infrastructure to an existing house. Other altered components and other applicable code provisions remain separate questions.
The same resource addresses newly constructed ADUs, duplexes, townhouses and electrical-service conditions. Use the applicable classification and complete provisions rather than borrowing one panel example for every project. This guide is not an electrical design checklist or an assertion that every new dwelling must install a battery.
04Battery permit decision checklist
Resolve these items before deciding which energy preparation task to order.
- +Installation versus readiness: identify actual equipment proposed now, future-ready provisions and whether any battery performance is being claimed in a building compliance model.
- +Building scope: distinguish an existing-home storage installation from a new house, new detached ADU, addition or alteration. Document the approved existing condition.
- +Related permits: identify PV, electrical-service, building and other applications, with their reviewing agencies, application dates and complete comments.
- +Responsible design: provide the electrical/system drawings and equipment information from the responsible designer or installer; label any not-yet-selected products.
- +Requested energy evidence: ask whether the AHJ needs CF1R or another applicable certificate for a building scope, a revision to an existing model, or documents in a separate discipline.
05Standalone storage versus PV plus storage
An owner adding storage to an existing home should explain whether PV exists, is being added or is unrelated to the proposal. Supply the relevant electrical package and the actual agency request. Do not assume a battery quotation or a PV contract establishes the need for a new whole-house CF1R.
Where PV/storage is incorporated into a building compliance package, the energy preparer needs the selected or clearly provisional system assumptions and the relevant design information. A model using one equipment arrangement should not be treated as final when the installation team is proposing a materially different arrangement.
PV requirements, battery-readiness requirements and installed storage are distinct concepts. The CEC maintains separate solar PV and BESS-ready guidance. An installed battery is not a generic substitute for every applicable PV provision, and a readiness note is not evidence of actual storage installation.
06When a CF1R package or model revision is relevant
For an applicable single-family building project, CF1R is design-stage evidence of energy compliance. If storage is part of the modeled design, coordinate its assumptions with the electrical/PV design and the chosen compliance approach. Do not claim credits from an unspecified battery or assume an optional future installation is already present.
A new dwelling usually has a broader energy documentation task independent of a homeowner’s backup-power preference. A storage-only installation at an existing dwelling presents a different question. Confirm the permit boundary and requested forms instead of automatically recreating the building’s complete envelope model.
If a permit model already exists and the PV/storage design changes, send the previous report and proposed changes for review. The preparer can identify whether the affected compliance documents need revision. Energy-report preparation does not include electrical design, equipment procurement, commissioning or utility authorization.
Energy-modeling service and exclusionsNew-construction documentationRevising reviewed energy documents
07Worked example: future-ready house versus existing-home battery
ILLUSTRATIVE ONLY: a new single-family dwelling has a qualifying service configuration and its designer is documenting BESS readiness rather than installing storage. The electrical team identifies the applicable readiness provisions. The energy preparer keeps the building’s compliance assumptions consistent and does not describe a future battery as installed equipment.
In a second case, an owner proposes storage at an existing house with existing PV and no new conditioned area. The applicant obtains the AHJ’s installation-document requirements and sends the system drawings. The new-construction BESS-ready rule is not simply imposed on that alteration as if the house were newly built.
If either project later proposes to claim battery performance in a required building model, the team revisits the supported assumptions. These examples do not determine a real system’s code compliance, backup duration, electrical safety or eligibility for an incentive.
08What to send, which date matters and who verifies
Provide the property/project information, AHJ-recorded application date, written scope, existing/proposed system drawings, equipment specifications, related PV design and any earlier CF1R or correction letter. For a larger building package, include architectural plans and relevant schedules rather than only a battery brochure.
The 2025 Energy Code applies to permit applications on or after January 1, 2026. Confirm the recorded date and the treatment of amendments or reapplications with the AHJ. A battery purchase date, interconnection request or installation appointment is not the building application-date record.
ECC is current terminology for applicable residential energy field verification; HERS remains relevant to older-cycle documents. Battery installation inspections should not automatically be called ECC verification. Identify the actual measures, forms and responsible participants. No incentive dollar amount, operating approval or backup-power guarantee is promised.
09Six battery-storage questions
Must every existing-home battery installation get a full CF1R?
No universal requirement is stated here. Ask which documents apply to the actual electrical/building scope and whether an existing energy model is affected before ordering whole-building analysis.
Is BESS-ready the same as installing a battery?
No. Readiness concerns provisions for future connection; installed storage is actual equipment. The CEC describes separate conditions and an installed-BESS exception within the single-family readiness provision.
Do the single-family BESS-ready provisions apply to additions?
The CEC’s 2025 BESS-ready FAQ says those provisions do not apply to additions or alterations. That does not remove other requirements for the affected building components or installation.
Can a future battery be entered as installed in a permit model?
Do not make that assumption. Identify actual equipment and supported design commitments with the preparer. Readiness infrastructure alone is not evidence of an installed storage system.
Does the energy report approve electrical installation or backup duration?
No. Electrical/system design, installation review and equipment performance are separate from energy-document preparation. Confirm each scope with the responsible professionals and agency.
What if the battery changes after the energy report is issued?
Send the earlier report, revised specifications and change summary. The preparer can assess affected modeling/documentation; do not silently substitute equipment behind a package that relies on different assumptions.
10Choose the next documentation step
Use the published residential/commercial square-footage menu to understand report pricing, then send a scoped request rather than assuming a full model is necessary. Field testing, acceptance testing, registry fees, CALGreen and AHJ permit fees are separate. Intake is not payment, production acceptance or permit approval. This is educational information, not legal advice; confirm the applicable requirements and documentation with the authority having jurisdiction (AHJ).
Start with the Title 24 decision hubDo I need Title 24 for solar?Do I need Title 24 for new construction?Do I need Title 24 for ev charger?Confirm the application’s code editionWhat to send for an energy reviewCF1R versus installation/verification recordsSee published PricingGet a Quote / upload plans
Sources
- CEC: 2025 Energy Code and January 1, 2026 effective date
- CEC: 2025 single-family battery energy storage system (BESS) ready FAQs
- CEC 2025 single-family solar PV FAQs: applicability, additions and ADUs
- CEC: 2025 single-family CF1R, CF2R and CF3R forms
- CEC: Energy Code Compliance (ECC) Program and transition questions
- CBSC: CALGreen Part 11, current editions, guides and checklists
- CBSC: 2025 Title 24 code changes, including Part 6 and Part 11