Multifamily Chapter Restructuring

Measure Description

The Statewide CASE Team proposes additional chapters for Title 24, Part 6, specific to multifamily buildings. The intent of the proposal is to:

1. Simplify compliance and enforcement by consolidating requirements for multifamily dwelling unit and common use areas into multifamily-specific chapters.
2. Create equity across multifamily building types, regardless of number of stories, through unified requirements.
3. Establish a platform from which the Energy Commission, Statewide CASE Team, and other stakeholders can investigate energy efficiency solutions unique to multifamily buildings (and distinct from single-family and nonresidential buildings) in future code cycles.

Per the proposed definition of multifamily building in Section 2.3.1.1, the proposed chapters would apply to multifamily buildings, defined as R-2 or R-4 occupancy. These generally include apartment buildings, condominiums, dormitories, townhouses greater than three habitable stories, dormitories, and assisted living facilities. Single family homes and other R-3 occupancy buildings would remain subject to the low-rise residential chapters, and hotel/motel and nonresidential buildings would remain subject to the nonresidential chapters. Mixed-use buildings would need to comply with the multifamily requirements for dwelling unit and common use areas and with applicable nonresidential requirements for all other portions of the building.

The three proposed chapters (Sections 160, 170, and 180) would cover mandatory requirements, prescriptive requirements and performance approach, and addition and alteration requirements for multifamily dwelling units and common area spaces. The content for each chapter would include portions of Title 24, Part 6 currently housed under the low-rise residential and nonresidential sections, marked-up for specific application to multifamily buildings. The chapters would include unified requirements that apply to multifamily buildings of all heights, with categorization by assembly or system type, and application to dwelling units or common areas. Generally, the unification would apply low-rise residential and nonresidential requirements to multifamily buildings as follows:

• Where cost effective, the more stringent of residential requirements for roofs/ceilings, walls, floors, and fenestration will apply to multifamily building envelopes by assembly type.
• Residential HVAC requirements of Sections 150.0, 150.1, and 150.2 apply to HVAC systems serving dwelling units. Nonresidential requirements of Sections 120.2 through 120.5, 140.4, and 141.0 apply to HVAC systems serving common use areas.
• Residential domestic hot water requirements apply to individual and central systems serving dwelling units. There is no resulting change in requirements because the 2019 high-rise residential requirements reference the low-rise residential requirements.
• Residential lighting requirements apply to dwelling unit lighting and outdoor fixtures controlled from within dwelling units. Nonresidential lighting requirements apply to common area and outdoor spaces. This includes removal of the exception for nonresidential occupancies up to 20 percent of the conditioned floor area and the eight-car threshold for compliance with nonresidential outdoor lighting requirements.
• Nonresidential electric power distribution requirements will apply to all multifamily buildings.

In addition to restructured 2019 Title 24, Part 6 requirements, the multifamily chapters may include new measures or changes adopted for residential and/or nonresidential buildings for 2022 Title 24, Part 6. The Energy Commission will consider each proposed measure individually, therefore these 2022 measure proposals are not discussed in this CASE Report. For more information on the proposed 2022 multifamily measures, view CASE Reports posted at https://title24stakeholders.com/measures/building-types/multifamily/2022/.

This CASE Report includes feasibility, market, energy, and cost analyses the Statewide CASE Team conducted for proposed changes that result in increased stringency for a specific multifamily building type. Each submeasure is described below, organized by category (envelope and space conditioning).

For changes that result in decreased stringency for a specific multifamily building type, the Statewide CASE Team has conducted energy analyses to capture the energy impact by dwelling unit and statewide. Such changes are proposed only for one of the following scenarios:

• To align between divergent 2019 Title 24, Part 6 Standards for nonresidential and residential where the higher stringency standard cannot be shown as cost effective across all multifamily buildings, given variance between the software modeling platforms.
• Where differentiation by construction type, physical aspect, or performance rating is not applicable. For example, windows that do not have durability, water penetration, or wind penetration concerns in buildings up to three habitable stories versus four habitable stories or more.
• When a common multifamily building component does not have a prescriptive option in current 2019 Title 24, Part 6 Standards. For example, non-attic roofs for low-rise multifamily.

Relevant Documents

Measure proposals, supporting documents, and other outside references will be made public as they become available.

• CASE Study Results Report – Multifamily Restructuring
• Final CASE Report Now Available
• Draft CASE Report – Multifamily Restructuring
• 2019 New and Revised Multifamily Prototypes
• Notes – May 5 – Multifamily Chapter Restructuring
• Presentation – May 5 – Multifamily Chapter Restructuring
• Proposal Summary – May 5 – Multifamily Chapter Restructuring
• Multifamily Chapter Restructuring Submeasure Tables
• Multifamily Energy Use Study