01Key facts / TL;DR
Yes, altered fenestration often needs Energy Code documentation under a permitted scope.
No, “like for like” is not a universal energy-documentation exemption.
It depends whether the windows belong to an alteration, addition or new-building package.
No, a product label alone does not replace the applicable compliance certificate.
02Identify the window work, not just the product
Replacing glazing, changing opening sizes and adding windows to new conditioned space are different project descriptions. Record which openings are retained, replaced, resized or new and where each sits in the building. A supplier quote saying “replacement windows” does not establish the applicable energy path or permit instructions.
Where permitted work alters regulated fenestration, the project team should identify applicable requirements and documentation. The answer is not automatically a whole-house performance model. A focused prescriptive alteration package may fit some scopes; other designs can involve supported performance analysis. The AHJ and preparer need the opening schedule and actual work to decide.
Do not infer a permit exemption or report waiver from the existing frame, similar appearance or unchanged room area. Conversely, do not assume every product purchase requires a model of the whole home. Ask what regulated work is being approved and which evidence the agency expects. This guide does not prescribe local review practices.
03Alteration windows and addition windows are not one rule
Windows in retained existing walls can be part of an alteration, while windows in a new conditioned addition belong to its addition scope. The applicable edition and pathway determine their requirements. A value or allowance used in one context should not be copied into the other without checking the actual provisions.
If both appear in one permit, mark them separately on the schedule and plans. An addition’s glazing quantity should not silently include unrelated retained windows, and an alteration form should not be treated as the complete new-addition package. Confirm which documents and calculations reconcile the combined work.
A performance method may evaluate design tradeoffs within an appropriate scope, but mandatory requirements and local provisions still apply. Do not buy a product on the assumption that a future model can compensate for any selection. Use the technical glazing guide for input concepts and the modeling service for project-specific option questions.
04A window-intake checklist that prevents guesswork
Provide the schedule alongside the plans so the preparer can trace each value to an opening.
- +Opening identity: label each window/glazed door on plans and elevations; state retained, replacement, resized or new and identify addition versus existing-house location.
- +Dimensions and area: provide supported sizes using the measurement basis required for the chosen calculation; a sales quantity alone does not describe glazing area.
- +Performance: supply whole-product U-factor and SHGC from applicable NFRC information or accepted documentation, matched to the actual product/configuration.
- +Building context: identify conditioned boundaries, orientation from the plans, affected assemblies, project classification and other envelope/system changes.
- +Application record: provide the AHJ, recorded date, prior report and complete comments if this is a correction. Identify product values that remain provisional.
05NFRC information supports the record; it is not the record
U-factor and solar heat gain coefficient describe different performance characteristics. The exact product and configuration matter; do not substitute a favorable center-of-glass number for the supported whole-product information used by the applicable procedure. Ask the designer/preparer what evidence is needed if a certified value or product match is uncertain.
Keep the specified schedule, supplier information and applicable labels consistent. A general brochure may list many products but not identify the one being installed. Site photos can help explain an opening, but do not by themselves establish dimensions, orientation or accepted performance values. Resolve unsupported inputs rather than inventing a climate-zone target or universal statewide numeric limit here.
If a substitution happens after report preparation, send the actual new values and affected openings back for review. A similar appearance or lower quoted price does not establish equivalence for compliance. The documentation should describe the selected design, not an earlier product that is no longer being ordered.
06Worked decision: a like-for-like order changes the schedule
ILLUSTRATIVE ONLY: an owner replaces several existing windows without enlarging the openings. The project is described as “like for like,” but the permit team still checks the applicable alteration provisions and documentation. The preparer receives the opening locations, supported U-factor/SHGC and application basis rather than assuming no energy review is necessary.
The owner later selects a different glazed-door configuration. The team compares the actual supported values and updates affected records if required. No invented numeric limit, exemption or passing result is supplied. The useful lesson is to make the product substitution visible before the final documents and installation records diverge.
07Forms, dates and construction responsibilities
The 2025 California Energy Code applies to permit applications on or after January 1, 2026. Confirm the AHJ-recorded date, especially for amendments or refiling. Where the single-family family applies, applicable CF1R-ALT or other design documentation should match the scope and selected method; use the current catalog rather than guessing a suffix.
Applicable CF2R installation and required CF3R verification are separate from design preparation. ECC is current terminology; HERS can remain on older-cycle records. A window-only project should not automatically be assigned every verification measure, and a supplier’s label does not certify the complete permit package. Confirm the actual requirements and responsible parties.
For multifamily or commercial glazing, establish classification and affected systems before choosing a form family. A single-family alteration certificate is not automatically valid for an apartment building or storefront. Provide building and tenant boundaries so the preparer can identify the appropriate documentation.
CEC single-family formsCF1R design-document helpCommercial envelope documentation
08Six window decisions
Does unchanged opening size automatically remove energy documentation?
No. “Like for like” does not establish a universal exemption. Identify the altered fenestration and ask the AHJ which energy requirements and records apply to the actual permit.
Can I use addition glazing rules for replacement windows?
Do not assume the same path. Addition and alteration scopes can have different provisions. Label openings by work category and have the preparer use the applicable edition and approach.
Is the NFRC label my Title 24 report?
No. It supports applicable product-performance inputs. The design certificate, plans and any required installation records still need to match the actual scope and product.
Should I send center-of-glass values from a brochure?
Provide the supported whole-product information required by the applicable procedure, matched to the actual configuration. Ask the designer/preparer about uncertain evidence rather than substituting an attractive but unrelated number.
Do window replacements always require a whole-house model?
Not necessarily. Some scopes can use focused prescriptive alteration documentation; others may involve performance analysis. Determine the task from the changed work, not from the assumption that every certificate is a full model.
What if the installed product differs from the report schedule?
Send the revised product values and affected opening references for coordinated review. The designer, preparer and installer should resolve the mismatch rather than relying on obsolete specifications.
09Choose 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 remodel?Do I need Title 24 for addition?Do I need Title 24 for commercial?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 CF1R, CF2R and CF3R forms
- CEC: 2025 single-family manual, Chapter 9 — additions, alterations and repairs
- CEC: 2025 single-family manual, including performance and existing-building chapters
- CEC: Energy Code Compliance (ECC) Program and transition questions