1.5 Scope and Application

1.5.1    Building Types

Though the Energy Standards apply to nonresidential and residential buildings, this compliance 'manual addresses only the requirements for low-rise residential buildings. A companion compliance 'manual addresses the requirements for nonresidential buildings, including hotels, motels, and high-rise residential buildings that are four or more stories high.

A.         Mixed Low-Rise Residential and Nonresidential Occupancies.  When a building includes both low-rise residential and nonresidential occupancies, the requirements are different depending upon the percentages of the conditioned floor that is occupied by each occupancy type:

1.   Minor Occupancy (Exception 1 to §100.0(f). When a residential occupancy occurs in the same building as a nonresidential occupancy, and if one of the occupancies is less than 20 percent of the total conditioned floor area, the smaller occupancy is considered a “minor” occupancy.  Under this scenario, optionally, the entire building may be treated as if it is the major occupancy for envelope, HVAC, and water heating. Lighting requirements in §140.6 through §140.8 or §150.0(k) must be met for each occupancy separately. The mandatory measures applicable to the minor occupancy, if different from the major occupancy, would still apply.

2.   Mixed Occupancy. When residential occupancy is mixed with a nonresidential occupancy, and if neither occupancy is less than 20 percent of the total conditioned floor area, these occupancies fall under different sets of standards and must be considered separately. Two compliance submittals must be prepared, each using the calculations and forms of the respective standards. Separate compliance for each occupancy, to the respective standards, is an option when one of the occupancies is a minor occupancy, as discussed in the paragraph above.

B.   The three-story designation relates to multifamily buildings, since all single family homes fall under the low-rise residential requirements regardless of the number of stories. An apartment building with three or fewer habitable stories falls under the low-rise residential standards while an apartment building that has more than three habitable stories falls under the nonresidential standards. High-rise residential dwelling units must still comply with the lighting and water heating requirements for low-rise residential buildings, for example, the Nonresidential Compliance Manual refers to Chapters 5 and 6 of this document.

In multifamily buildings, lighting in common areas is subject to all nonresidential requirements if the common area conditioned floor area (CFA) exceeds 20 percent of the building CFA. Where the common area does not exceed 20 percent of the building CFA, lighting must meet mandatory requirements – a choice of high-efficacy lighting or automatic controls. (See §150.0(k)12.)

C. The definition of a habitable story in the California Building Code (CBC) is used with the Energy Standards. Mezzanines are not counted as separate habitable stories nor are minor conditioned spaces such as an enclosed entry stair that leads to an apartment or dwelling unit on the next floor. A habitable story is one that contains space in which people may live or work in reasonable comfort, and that has at least 50 percent of the associated volume above grade.

D.   Live/work buildings are a special case since they combine residential and nonresidential uses within units. Such buildings are a common form of new construction in San Francisco and some other urban areas of the state. Even though live/work spaces may be used for an office or a studio, they are typically heated and/or cooled like a residential building. For this reason the residential standards are more suitable and the Energy Commission has made this determination: Either the low-rise or high-rise residential standards apply, depending on the number of habitable stories.

However, lighting in designated workspaces in live/work lofts must comply with the nonresidential prescriptive lighting requirements. See Chapter 5 of the Nonresidential Compliance 'Manual and §140.6 for more information.

Table 1-2: Building Types Covered by the Low-Rise Residential and Nonresidential Standards

1.5.2    Explanation of Terms

The term building type refers to the classification of buildings defined by the CBC and applicable to the requirements of the Building Energy Efficiency Standards. This 'manual is concerned with the Energy Standards that apply to all low-rise residential buildings, which includes all single-family residential and multifamily buildings with three or fewer habitable stories in the entire building. A multifamily building with four or more habitable stories is under the scope of the nonresidential requirements, but the dwelling units must meet the lighting, water heating, and setback thermostat requirements for low-rise residential buildings. A multifamily building contains multiple dwelling units that share common walls (single family attached) and may also share common floors or ceilings (apartments).

All residential buildings not in the above low-rise category are covered in the 2019 edition of the Energy Commission's Nonresidential Compliance Manual. (See Parts 1.1 and 1.2.)

A.   A single-family building is a single dwelling unit of occupancy group R-3, as defined in the CBC, that stands separate from other dwelling units but may have an attached garage.

B.   A multifamily building is a dwelling unit of occupancy group R, as defined in the CBC; that shares a common wall and/or floor/ceiling with at least one other dwelling unit. See Chapter 8 for more information on multifamily energy compliance. A single family attached building is a dwelling unit of occupancy group R that shares a common wall with another dwelling unit.

C.   An addition to an existing building increases both the conditioned floor area and volume of a building, which can be new construction or added space conditioning to an existing unconditioned space. See Chapter 9 for more information on energy compliance of additions.

D.   An existing building is a building erected prior to the adoption of [the current] code, or one for which a legal building permit has been issued." (CBC, Part 2)

1.5.3    Building Orientation

Building orientation can affect the energy use of a building, particularly in cooling dominated climate zones with a high amount of west-facing glass. Some prescriptive requirements and performance modeling inputs for compliance with the Energy Standards require a description of the building orientation. 

A.   ‘East-Facing

"East-facing is oriented to within 45 degrees of true east, including 45°0'0" south of east (SE), but excluding 45°0'0" north of east (NE)." §100.1.

B.   ‘North-Facing

"North-facing is oriented to within 45 degrees of true north, including 45°0'0" east of north (NE), but excluding 45°0'0" west of north (NW)." §100.1.

C.   ‘South-Facing

"South-facing is oriented to within 45 degrees of true south, including 45°0'0" west of south (SW), but excluding 45°0'0" east of south (SE)." §100.1.

D.   ‘West-Facing

"West-facing is oriented to within 45 degrees of true west, including 45°0'0" due north of west (NW) but excluding 45°0'0" south of west (SW)." §100.1.

1.5.4    Historical Buildings

Exception 1 to §100.0(a) states that qualified historic buildings, as regulated in the California Historical Building Code (Title 24, Part 8) or California Building Code, Title 24, Part 2, Volume I, Chapter 34, Division II are not covered by the Building Energy Efficiency Standards. Section140.6(a)3 clarifies that lighting systems in qualified historic buildings are exempt from the lighting power allowances only if they consist solely of historical lighting components or replicas of historical lighting components. If lighting systems in qualified historic buildings contain some historical lighting components or replicas of historical components, combined with other lighting components, only those historical or historical replica components are exempt. All other lighting systems in qualified historic buildings must comply with the Building Energy Efficiency Standards.

The California Historical Building Code (CHBC) Section 8-102.1.1 specifies that all nonhistorical additions must comply with the regular code for new construction, including the Building Energy Efficiency Standards. CHBC Section 8-901.5 specifies that when new or replacement mechanical, plumbing, and electrical (including lighting) equipment or appliances are added to historic buildings they should comply with the Building Energy Efficiency Standards, including the Appliance Efficiency Regulations.

The California State Historical Building Safety Board has final authority in interpreting the requirements of the CHBC and determining to what extent the requirements of the Building Energy Efficiency Standards apply to new and replacement equipment and other alterations to qualified historic buildings. In enacting the State Historical Building Code legislation, one of the intents of the Legislature was to encourage energy conservation in alterations to historic buildings (Health and Safety Code Section 18951).

Additional information about the CHBC can be found on the following website:

http://www.dgs.ca.gov/dsa/AboutUs/shbsb.aspx

Or contact the SHBSB at (916) 445-7627.

1.5.5    Exempt Buildings

The following building types are exempt from the prescriptive and performance standards:

A.   Seasonally occupied agricultural housing limited by state or federal agency contract to occupancy not more than 180 days in any calendar year (Exception 1 to §100.0(e)2D); however, these buildings must comply with the applicable mandatory requirements.

B.   Based on discretion of building officials, 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 the mandatory and prescriptive requirements of the Energy Standards.

1.5.6    Building Systems Covered

The low-rise residential standards affect the design of the building envelope; the heating, ventilation and air-conditioning (HVAC) system; the water heating system; and the lighting system. The Energy Standards do not apply to residential appliances (Appliance Efficiency Regulations may apply), elevators or dumbwaiters, or portable lighting systems that are plugged into a wall outlet. Only hardwired lighting is regulated, which includes lighting that is a permanent part of the building.

1.5.7    Additions, Alterations and Repairs

Additions, alterations, and repairs are common construction projects for California homeowners. The Energy Standards apply to both additions and alterations, but not to repairs. See Chapter 9 for details.

A.   Additions are changes to an existing building that increase both conditioned floor area and volume.

B.   Chapter 9 includes detailed guidance on showing compliance for accessory dwelling units and converting an existing space to conditioned space.

C.   Alterations, that are not additions, are changes to the envelope, space-conditioning system, water-heating system or lighting system of a building.

D.   Repairs are the reconstruction or renewal of any part of an existing building for maintenance purposes and are not under the scope of the standards. Replacement of any component systems (such as reroofing,) or equipment for which there are requirements in the Energy Standards is considered an alteration and not a repair.