An accessory dwelling unit needs an Energy Code strategy that matches how the project is classified and permitted. A detached new ADU, an attached addition, and a conversion of existing space can follow different provisions; the CEC’s 2025 ADU FAQ tells project teams to identify whether the scope is new construction, an addition, or an alteration.

Begin with Poppy Energy’s Title 24 compliance reporting service when the design needs an energy model or compliance package. If the approved documents list field verification, the California testing-required guide explains how to read that scope, and the QII field-verification hub covers coordination when QII appears in the approved compliance path.

Title 24 Report and ADU Classification

The report should reflect the ADU’s actual geometry, envelope, climate zone, orientation, systems, water heating, ventilation, and project classification. The CEC’s 2025 compliance-software page says approved programs are authorized for specific occupancies and project scopes, including new construction, additions, and alterations.

For single-family documents, the 2025 forms directory lists different CF1Rs for newly constructed buildings, additions, alterations, and simple non-ECC scopes. Use the form generated for the approved path rather than borrowing one from another ADU.

Before permit submission, confirm:

Whether the ADU is detached new construction, attached addition, or conversion/alteration
Applicable code cycle based on permit-application timing
Prescriptive or performance compliance approach
Conditioned floor area and assemblies shown on plans
HVAC, duct, ventilation, and water-heating design
ECC Feature Summary and anticipated construction-stage verifications

Permit applications submitted on or after January 1, 2026 must use approved 2025 compliance software, according to the CEC.

QII Timing

Quality Insulation Installation (QII) applies when it appears in the project’s approved compliance path. The controlling 2025 Reference Residential Appendix RA3.5 contains the QII installation and ECC-rater inspection protocols and requires the applicable installation certificate to be available for each verification inspection.

Use Poppy Energy’s QII field-verification hub for scheduling scope and the QII inspection-process guide for project-stage coordination.

Poppy scheduling recommendation: hold a pre-installation review with the builder, insulation contractor, energy consultant, and ECC-Rater. Compare the approved assemblies with the proposed materials, ask the rater when each scoped condition must be accessible, and resolve substitutions before installation. This coordination advice does not replace the project-specific RA3.5 procedure.

QII is not a national RESNET HERS Index rating. The CEC explains that California compliance FV&DT moved from HERS to ECC while optional whole-house rating remained separate in its ECC Program FAQ.

HVAC and Duct Choices

Decide early whether the ADU uses a ducted system, ductless system, shared equipment, or dedicated equipment, then model and document the selected design. The 2025 forms directory contains separate mechanical CF2R and CF3R records for space-conditioning systems, ducts, airflow, fan efficacy, refrigerant charge, and other features, demonstrating that verification scope follows the selected system and CF1R.

If the design changes after permit—such as switching equipment type, moving ducts, or changing model numbers—send it to the energy consultant before installation. The CF1R’s purpose is to demonstrate design and equipment compliance at permit application, as Energy Code Ace explains, so the field installation should be traceable to that approved record.

Ventilation

Mechanical ventilation is part of the residential compliance-document set. The CEC’s 2025 single-family forms library includes CF2R-MCH-27-H for indoor air quality and mechanical ventilation among the current forms.

Coordinate the ventilation equipment, controls, duct route, termination, and commissioning access before finishes. Do not assume an operable window or a bathroom exhaust fan automatically satisfies the project’s whole-dwelling ventilation design; follow the approved documents and the applicable 2025 standards in the CEC publication.

Water Heating and Equipment Match

The water-heating design depends on ADU classification, size, compliance path, equipment type, and distribution. The CEC’s 2025 ADU FAQ provides project-specific answers for new detached ADUs and ADU additions, including limited prescriptive options for certain dwelling units or additions of 500 square feet or less.

Do not generalize those limited options to every ADU. Compare the installed water heater’s type, fuel, location, efficiency data, controls, and distribution with the CF1R. If equipment changes, ask the energy consultant whether the compliance analysis and forms need revision.

Use the same match process for HVAC and ventilation equipment: record complete model numbers, associate each unit with its CF1R system identifier, and retain manufacturer documentation for the installer and rater workflows.

Verification Stages

Poppy scheduling recommendation: build an ADU coordination schedule from the ECC Feature Summary, then confirm the applicable procedure and timing with the rater:

Stage	Coordination questions
Before permit	Is the classification, model, CF1R, and feature summary complete?
Framing/air barrier	Does a listed QII or envelope measure require visible framing-stage observation?
Insulation	Are assemblies, labels, fitting, and air-barrier details visible for any listed QII stage?
Mechanical rough/installation	Do ducts, ventilation, and equipment match the approved system IDs?
Startup/testing	Are utilities, controls, filters, grilles, registers, and safe access ready for listed tests?
Documentation	Are installer CF2Rs and rater CF3Rs complete in the provider workflow?

This is a coordination table, not a universal list of mandatory ADU inspections or readiness conditions. The controlling measures are the ones identified on the approved certificate; the CEC counter sheet states that required FV&DT is specified there. When a listed mechanical procedure applies, RA3.1 defines the applicable duct-test configuration and RA3.3 defines airflow-test operating conditions such as filter and register position.

Permit Closeout

Before requesting final inspection, assemble the current CF1R, applicable installer CF2Rs, applicable rater CF3Rs, correction or revision records, and any documents requested by the jurisdiction. The CEC forms library separates these design, installation, and verification stages.

Confirm registry completion when ECC measures apply. The CEC identifies ECC-Providers as operators of approved residential data registries, and CHEERS notes that building departments use registry information to confirm compliance before approval.

Finally, follow the local building department’s submission and inspection process. The rater verifies listed energy measures; the building department performs its own enforcement and final-inspection role. Planning those responsibilities from the report stage prevents the common late discovery that a wall was closed, equipment changed, or a required record was never registered.

California ADU ECC and Title 24 Requirements Guide