This chapter covers the requirements for all dwelling units and common use areas in multifamily buildings for both newly constructed buildings and additions or alterations to existing buildings. Multifamily buildings include the following:

• A building of occupancy groups R-2, other than a hotel/motel building or timeshare property,
• A building of occupancy group R-3 that is a non-transient congregate residence, other than boarding houses of more than 6 guests and alcohol or drug abuse recovery homes of more than 6 guests, and
• A building of occupancy group R-4.

Single-family homes, duplexes, triplexes, and all townhouses (regardless of number of habitable stories) are subject to the single-family requirements and covered in the Residential Compliance Manual.

Spaces in multifamily buildings include both dwelling units and common use areas. Dwelling unit requirements apply to living, sleeping, eating, cooking, and sanitation spaces within a single unit. A single dwelling unit may include shared living spaces with multiple sleeping rooms, such as in a dormitory. Dwelling unit requirements covered in this chapter share few requirements with nonresidential buildings. Common use area requirements apply to spaces outside the dwelling unit that are shared by building owners, residents, and their guests. Spaces used by building managers and maintenance staff qualify as common use areas.

Due to the similarity of requirements for common use areas and nonresidential spaces, this chapter frequently references other chapters of the Nonresidential Compliance Manual for common use areas. All other occupancies in a mixed-use building are subject to the nonresidential requirements in Chapters 3 through 10.

The following building types are outside the scope of the Energy Code:

• Historical buildings, as defined by the in the California Historical Building Code (Title 24, Part 8). In alterations to historical buildings, replacement lighting fixtures that are not historic or replicas of historic fixtures must comply with applicable indoor and outdoor lighting requirements.
• At the discretion of the enforcement agency, temporary buildings, temporary outdoor lighting or temporary lighting in an unconditioned building, or structures erected in response to a natural disaster (Exception 2 to §100.0(a)). These buildings may also be exempt from mandatory requirements of the Energy Code.
• Buildings being converted to a multifamily occupancy from another occupancy must comply with applicable requirements for additions or alterations to multifamily buildings.

Example 11-1

Question

Three stories of residential dwelling units are planned over a first story that includes retail and restaurant occupancies. Which occupancies need to comply with the multifamily standards?

Answer

The "R" occupancy (dwelling units and common use areas) will be subject to the MF requirements, the retail (occupancy "M") and restaurant (occupancy "A") are subject to the nonresidential standards. If using the performance approach, the combined energy budget is used to determine compliance.

Example 11-12

Question

Does a four-story townhouse need to comply with the single-family standards or multifamily standards?

Answer

Townhouses, regardless of number of habitable stories, are covered under the single-family standards.

Example 11-3

Question
An apartment building has three stories of apartments, and a garage on the first floor. What are the applicable compliance requirements?

Answer

Dwelling unit and common use area spaces must comply with the multifamily standards. The parking garage must meet applicable nonresidential lighting and covered process requirements.

Multifamily building dwelling unit requirements align closely with single-family requirements, while common use area requirements align closely with nonresidential requirements. All dwelling unit requirements are covered in the multifamily chapter. In some cases, headings for common use spaces reference other nonresidential chapters. Table 11-1 shows which chapter of this manual covers dwelling units vs. common areas.

^{Source: California Energy Commission}

Each subchapter contains the following elements:

• A summary of what is new for the 2022 code cycle.
• Presentation of a specific topic in each subsection for newly constructed buildings
• A discussion of additions and alterations for existing buildings
• Compliance and enforcement
• Code in practice

Mandatory requirements, prescriptive requirements, and performance options are described within each subsection.

Each technical chapter or subsection has a Code in Practice section with example projects that demonstrate compliance. The example projects are a two-story multifamily garden complex and a five-story mixed use building.

The two-story garden complex example has multiple eight-unit buildings with dwelling unit access from the building exterior and no interior common use areas. Building features and mechanical components include:

• Slab-on-grade ground floor
• Wood framed walls
• Vented attic
• Split heat pump with ducts in the attic and dropped soffit
• Individual water heaters
• Carport parking

The five-story mixed-use building example has ground floor retail and common use areas, with four residential floors and 88 dwelling units with above. Building features and mechanical components include:

• Concrete podium ground floor
• Below ground parking garage
• Wood frame construction on the second through fourth floors
• Metal frame construction on the fifth floor
• Flat roof with mechanical equipment and outdoor living space
• Split heat pump
• DOAS serving common use areas
• Central water heating serving the whole building

The most significant change in the 2022 Energy Code affecting multifamily buildings is the consolidation of dwelling unit and common use area requirements into three standalone subchapters. These changes result in consistent requirements across multifamily buildings, while the 2019 Energy Code had separate requirements for multifamily buildings up to three habitable stories and buildings with four or more habitable stories. There are also changes in requirements related to indoor air quality, space conditioning, and domestic hot water. These are further described in the What’s New for the 2022 Energy Code section and in each technical Section 11.3 through 11.9.