- Multifamily Compartmentalization Requirements
- Alternative Compliance Procedure to Nonresidential Appendix NA4 for Relocatable Public School Buildings
- Energy Code Support Center Updates
- Economizer FAQs
- Residential Dwelling Unit Lighting FAQs
- 2025 Water Heater Efficiency Guide
- 2025 Single-Family Water Heater Alterations Guide
- 2025 Nonresidential Cool Roofs FAQs
- 2025 Nonresidential Vestibules FAQs
- Q&As
- Envelope
- Solar Heat Gain Coefficient, Climate Zone 15
- NFRC 700 and Compliance Modeling Approach
- Covered Processes
- Parking Garage CO Sensors
- Envelope
Articles
Multifamily Compartmentalization Requirements
The mandatory whole-dwelling mechanical ventilation requirements for multifamily dwellings were updated in the 2025 Energy Code;exhaust-only ventilation systems are no longer acceptable to meet the whole-dwelling ventilation requirements under Section 160.2(b)2Aivb. A balanced or supply-only whole-dwelling ventilation system must be installed. Additionally, regardless of the type of whole-dwelling ventilation system being installed, compartmentalization testing is required for all dwellings. Section 160.2(b)2Aivb2 requires the air leakage rate of each dwelling to be less than or equal to 0.3 cubic feet per minute at 50 Pa (0.2 inch of water) per square foot of dwelling unit envelope surface area.
NOTE: The mandatory whole-dwelling mechanical ventilation requirements for multifamily dwellings do not apply to additions or alterations to multifamily buildings, see Sections 180.1 and 180.2, respectively.
Multifamily, three or fewer habitable stories
For multifamily buildings with three habitable stories or less, the dwelling unit air leakage must be confirmed through field verification and diagnostic testing (FV&DT) by a certified Energy Code Compliance Rater (ECC-Rater) in accordance with the procedures in Reference Residential Appendix RA3.8.
Prior to FV&DT, the builder or installing contractor must test the dwelling unit air leakage and document their results on the LMCI-MCH-24-H form for each dwelling unit. After confirming these results, the ECC-Rater will conduct FV&DT per RA3.8 and document their dwelling unit air leakage results on the LMCV-MCH-24-H form. The ECC-Rater may sample and test one out of a group of seven dwelling units.
All applicable Certificates of Compliance (LMCC), Installation (LMCI), and Verification (LMCV) must be completed and registered with an approved ECC-Provider data registry. See Summary 1 below for more details.
NOTE: If the ECC-Rater conducts 100 percent testing for all dwelling units, then the builder/installing contractor may use their results to complete the LMCI-MCH-24-H form.
Multifamily, four or more habitable stories
For multifamily buildings with four or more habitable stories, the dwelling unit air leakage may be confirmed through two paths: using an ECC-Rater or using a Certified Mechanical Acceptance Test Technician (CMATT).
The ECC-Rater path follows the ECC-Rater process described above, with a few differences. FV&DT by the ECC-Rater will be similar but will follow the procedures in Reference Nonresidential Appendix NA2.3. The builder or installer must document their dwelling unit air leakage test results for all dwelling units on the NRCI-MCH-E form (Section F, Table “Multifamily Dwelling Unit Ventilation Systems”). The nonresidential Certificates of Compliance (NRCC) and Installation (NRCI) forms are not required to be registered with an approved ECC-Provider data registry. The ECC-Rater must collect the NRCI-MCH-E form and retain it for their records. ECC-Raters will be asked to produce the collected NRCI-MCH-E forms for ECC-Providers’ quality assurance reviews. Therefore, the CEC recommends that ECC-Raters upload the NRCI-MCH-E to the residential data registry.
After confirming the builder’s or installing contractor’s test results, the ECC-Rater will conduct FV&DT per NA2.3 and document their dwelling unit air leakage results on the NRCV-MCH-24-H form. The ECC-Rater may sample and test one out of seven grouped dwellings.
All applicable nonresidential Certificates of Verification (NRCV) must be completed and registered using an approved ECC-Provider data registry. As discussed above, the CEC recommends also uploading the NRCI-MCH-E forms. See Summary 1 below for more details.
NOTE: If the ECC-Rater conducts 100 percent testing for all dwelling units, then the builder/installing contractor may use their results to complete the NRCI-MCH-E form.
For the CMATT path, FV&DT is performed by a CMATT. FV&DT follows the procedures in Reference Nonresidential Appendix NA1.9. The builder or installer must document their air leakage testing results for all dwelling units on the NRCI-MCH-E form, Section F. The CMATT must collect the NRCI-MCH-E form and retain it for their records. CMATTs will be asked to produce the collected NRCI-MCH-E forms for Acceptance Test Technician Certification Providers’ (ATTCP) quality assurance reviews. Therefore, the CEC recommends that CMATTS upload the NRCI-MCH-E to an approved ATTCP database.
After confirming the builder’s or installing contractor’s test results, the CMATT will conduct FV&DT per NA2.3 procedures and document their dwelling unit air leakage results on the NRCA-MCH-21-H form. Under this alternative approach, sampling is not allowed; the CMATT must test all dwelling units. All applicable nonresidential mechanical Certificates of Acceptance (NRCA) must be recorded using an approved ATTCP database. As discussed above, the CEC recommends also uploading the NRCI-MCH-E forms. See Summary 1 below for more details.
NOTE: the CMATT may also be the installing contractor and may conduct the required dwelling leakage testing and complete both the NRCI-MCH-E and NRCA-MCH-21-H forms for each dwelling unit when applicable.
Please visit the ECC-Provider and ATTCP program pages for more general information.
Summary 1
- Multifamily, three for fewer habitable stories
- Verifying Technician: ECC-Rater
- Installation Form: LMCI-MCH-24-H
- Verification Form: LMCV-MCH-24-H
- Registration/Document Retention: All forms must be registered using an approved ECC-Provider Data Registry
- Sampling: ECC-Rater tests one out of seven after all dwelling units have been tested by the builder/installer
- Test Procedures, Requirements: RA3.8
- Multifamily, four or more habitable stories, using ECC-Rater
- Multifamily, three for fewer habitable stories
- Verifying Technician: ECC-Rater
- Installation Form: NRCI-MCH-E
- Verification Form: NRCV-MCH-24-H
- Registration/Document Retention: NRCV-MCH-24-H must be registered using an approved ECC-Provider Data Registry. NRCI-MCH-E is not registered but must be retained by ECC-Rater and uploaded to an ECC-Provider data registry.
- Sampling: ECC-Rater tests one out of seven after all dwelling units have been tested by the builder/installer
- Test Procedures, Requirements: NA2.3
- Multifamily, four or more habitable stories, using ATT
- Verifying Technician: Certified Mechanical ATT (CMATT)
- Installation Form: NRCI-MCH-E
- Verification Form: NRCA-MCH-21-H
- Registration/Document Retention: NRCA-MCH-21-H must be recorded using an approved ATTCP database. NRCI-MCH-E must be retained by the CMATT and uploaded to an ATTCP database.
- Sampling: Not allowed. All dwelling units must be tested by builder/installer and by CMATT
- Test Procedures, Requirements: NA1.9
Announcements
Alternative Compliance Procedure to Nonresidential Appendix NA4 for Relocatable Public School Buildings Approved
The CEC has approved in its July Business meeting an alternative procedure to the Reference Appendices, Nonresidential Appendix NA4 ‘Compliance Procedures for Relocatable Public School Buildings’ for demonstrating compliance with the 2025 Energy Code. The alternative procedure introduces climate zone groups and allows compliance to be demonstrated by modeling the energy use of relocatable public school buildings in a representative climate zone for each group. The procedure requires that the building demonstrate compliance oriented along all four cardinal azimuths in the representative climate zone for a given group.
- Climate zone 16 represents Group A (CZ 1, 16)
- Climate zone 4 represents Group B (CZ 2, 3, 4, 5)
- Climate zone 10 represents Group C (CZ 6, 7, 8, 9, 10)
- Climate zone 14 represents Group D (CZ 11, 12, 13, 14)
- Climate zone 15 is kept separate from the groups.
This alternative procedure aligns with the Division of the State Architect’s (DSA’s) Procedure PR 18-02, CALGreen/Energy Code Review (CGE) for Pre-Check (PC) building designs and the construction, relocation and/or alteration of relocatable buildings.
Energy Code Support Center Updates
Please visit the Energy Code Support Center webpage for resources, including fact sheets, FAQs, guides, presentations, training classes, videos, and links to additional resources. New resources include:
Q&As
Does the solar heat gain coefficient (SHGC) limit for single family homes in Climate Zone 15 vary by window replacement area?
Yes. For Climate Zone 15:
- Newly constructed single-family buildings must meet a maximum area-weighted average SHGC of 0.20 (per Section 150.1(c)3A).
- When replacing up to 75 square feet of vertical fenestration, the maximum area-weighted average SHGC is 0.35 (per Exception 1 to Section 150.2(b)1B).
- When replacing more than 75 square feet of vertical fenestration, the maximum area-weighted average SHGC is 0.23 (per Exception 3 to Section 150.2(b)1B).
Will NFRC 700 and the Component Modeling Approach be retired?
Yes. The National Fenestration Rating Council (NFRC) retired the Component Modeling Approach (CMA) under NFRC 705 and the site-built fenestration certification portions of NFRC 700 on May 29, 2026. These commercial and site-built procedures are being replaced by NFRC 715: Commercial Energy Performance Certification Program.
Note: NFRC 700 itself (the overall product certification program) is not replaced by NFRC 715. Instead, it transitions to the new NFRC 7000 series documents. Only the site-built portion moves to NFRC 715.
Is the sensor reading differential of 15 ppm provided in Section 120.6(c)7ii applicable to all parking garage projects?
No. Sections 120.6(c)7ii and iii provide examples of readings that may indicate a parking garage CO sensor failure. Reference Appendix NA7.12.2, Steps 4 and 5 describe the sensor differential readings needed to show a failure. For unoccupied periods, a single sensor with a differential of 30% over four hours, when compared to all sensors in the garage, is considered to have failed. For occupied periods, a single sensor with a differential of 30% over four hours, when compared to sensors in the same proximity zone, is considered to have failed.