FARBER ENERGY DESIGN

 

home page

contact information

firm profile

energy-efficient design

efficiency incentive programs

energy analysis checklists

fenestration

resources/links

 

TITLE 24 ENERGY STANDARDS

 

Click on topic listed below to jump to that topic:  

 

General Information

 

 

 

Applicability: New Building Types, Building Alterations

 

 

 

New Nonresidential, High-Rise Residential, and Hotel/Motel Buildings

 

 

 

New Single-Family and Low-Rise Multi-Family Residential Buildings

 

 

 

Building Alterations and Additions

 

 

 

Fenestration Modeling

 

 

 

 

2016 BUILDING ENERGY STANDARDS: General Description

 

“Title 24” is shorthand for California’s building energy efficiency standards, which reside in state code Title 24 Part 6.  The California Energy Commission (C.E.C.) is responsible for developing Title 24.  Enforcement is the responsibility of local building departments (or DSA with respect to public schools).  Title 24 was first adopted in 1978, and is updated approximately every three to four years.

The 2016 Title 24 Standards became effective on January 1, 2017.  Unlike the major changes that occurred with the 2013 Standards – especially with the new, and sometimes errant, Performance compliance computer programs that employed new modeling “engines” for both nonresidential and residential buildings – the amount of change in the 2016 Standards is relatively minor.  True, the California Energy Commission expects that the standards for low-rise residential buildings will be around 30% more stringent than the 2013 code; but this jump is based mainly on new domestic water heating and new attic insulation baseline requirements.  Relatively few changes are included in the nonresidential standards – which still have not caught up with the LED lighting revolution (expect that to occur with the 2019 Standards). 

Standards efficiency requirements increase due to technological advances, State laws to address climate change, and the legislated requirement that new low-rise residential buildings achieve net zero energy by 2020, and that nonresidential/high-rise residential buildings achieve net zero energy by 2030.

See below for specific information on Title 24 requirements for nonresidential buildings and for residential buildings.

 

 

Another source of Title 24 information is the California Energy Commission.  See C.E.C. on the Resources/Links page of this site.

 

 

 

APPLICABILITY

 

Title 24 envelope and mechanical requirements apply to "conditioned" portions of all new buildings, building additions, and alterations, except as listed under “Buildings/Occupancies Exempt From Title 24” (see below).  Lighting efficiency is regulated in conditioned spaces, unconditioned enclosed spaces, and in most developed outdoor spaces.

Title 24 building compliance calculations typically pertain to the building “envelope”, space conditioning systems, indoor lighting, and for projects with dwelling units, the domestic water heating system.  For spaces maintained outside human comfort temperatures, and for spaces that have a very low heating or cooling capacity, only lighting compliance is required (contact F.E.D. for details).  There are also Title 24 mandatory measures for envelope, mechanical and lighting systems (examples: automatic daylight and motion sensor lighting controls, thermostat requirements, infiltration limiting measures, and ventilation for air quality). 

See below for specific information on Title 24 requirements for nonresidential buildings and for residential buildings.

 

BUILDING/OCCUPANCY EXEMPTIONS FROM TITLE 24:

 

·   UBC group I and U occupancies (such as hospitals and prisons) are entirely exempt.

 

·   Historical buildings (as defined in State Historic Building Code, Title 24 Part 8): Most lighting alterations are subject to Title 24 requirements.  Envelope and mechanical alterations are exempt.  Additions to historic buildings must fully meet Title 24.

 

 

 

COMPLIANCE APPROACHES

 

There are two basic approaches to demonstrate compliance with building energy efficiency requirements:  prescriptive, and performance.  These approaches are available for both nonresidential and residential buildings, for both new construction and for alterations. 

Prescriptive compliance entails designing all building systems to meet specific prescribed requirements.  There are no trade-offs allowed between the different primary building systems (envelope, indoor lighting, mechanical). 

Performance compliance requires creating a computer-based model of the project, running an hourly energy simulation through a typical weather year, demonstrating that the proposed energy budget does not exceed the allowed energy budget (the latter being based essentially on the project’s geometry and space usage, if its systems and components complied with the code’s prescriptive requirements). 

For outdoor lighting, there is only a prescriptive compliance approach for nonresidential and larger multi-family projects, and only mandatory efficiency and control requirements for single-family and small multi-family projects.

 

return to top of page

 

 

NEW NONRESIDENTIAL, HIGH-RISE RESIDENTIAL*

and HOTEL/MOTEL BUILDINGS

 

Major changes in the 2016 Standards

 

General Items:

 

  Minimum roof and wall insulation:  Some relaxation of requirements.  Where metal frame walls essentially had to have insulative sheathing in order to meet the minimum insulation requirement under the 2013 code, now R-25 batt in 8” metal studs meet the minimum insulation requirement.

  Prescriptive compliance roof and wall insulation:  Some modest increases in insulation requirements for some assemblies in some climate zones. 

  Demising walls (walls separating conditioned and unconditioned spaces):  R-13 between metal framing no longer meets the requirement. For 4” metal stud walls, R-13 batt plus R-2 continuous insulative sheathing works; R-22 batt in 8” metal studs at 24” o.c. also meets the requirement.  For wood framed walls, R-13 batt where 2x4’s are 24” o.c., or R-15 batt for 2x4’s at 16” o.c., can meet the requirement.

  Alterations:  No major changes from the 2013 Standards.

 

Prescriptive compliance:

Note: These and all prescriptive requirements are optional under the performance compliance approach; under the performance approach, measures that are not up to prescriptive requirements result in an energy “penalty” that will need to be offset with energy improvements (i.e. features that exceed the prescriptive requirements).

 

  Fenestration:  No changes from the 2013 Standards.

  Cool Roofs:  No changes from the 2013 Standards.

  Space Conditioning Systems:  Only one major change to the prescriptive compliance requirements: automatic system shut-off (interlock) at operable wall and roof openings.  Doors with automatic closers are exempt.  Alterations are exempt.

  Indoor lighting power:  The lighting power allowances for certain interior tasks are reduced in response to advances in lighting technology.  Examples: Conference/convention/multi-purpose changed from 1.4 to 1.2 watts/sq.ft., lounge changed from 1.1 to 0.9 watts/sq.ft.  No changes to office area lighting power allowance.

  Indoor lighting controls:  The current mandatory occupancy sensor (OS) requirement for small offices, conference rooms, classrooms and multi-purpose rooms is changed to require the use of either partial-on OS control, or “vacancy sensor” control (the latter control is where turning on the lights is totally manual, lights turn off automatically when space vacant).

Outdoor lighting power:  The lighting power allowances for certain area types is reduced in response to advances in lighting technology. 

Outdoor lighting controls:  Dimming requirement expanded to include outdoor sales areas.

 

Performance compliance:  No major changes from the 2013 Standards.  The performance modeling engine that debuted with the 2013 code, and that the CEC requires all performance compliance calculations to use, has become more stable and reliable.

 

* High-rise is four habitable stories or more above grade

 

 

return to top of page

 

 

NEW SINGLE-FAMILY and LOW-RISE*

MULTI-FAMILY RESIDENTIAL BUILDINGS

 

Major changes in the 2016 Standards

 

Prescriptive compliance:

Note: These and all prescriptive requirements are optional under the performance compliance approach; under the performance approach, measures that do not measure up to prescriptive efficiency requirements will result in an energy “penalty” in the performance energy budget.  The efficiency penalty will need to be offset with energy improvements (i.e. features that exceed the prescriptive requirements).

 

  Fenestration:  No changes to prescriptive compliance areas and efficiency as compared to the 2013 Standards.

  Roof Insulation: The mandatory minimum value is decreasing from R-30 to R-22.  The prescriptive requirement for designs with ducts in attic space now includes insulation at the roof plane in addition to the ceiling insulation – called “high-performance” roof insulation.  The goal is to keep the attic temperature close to the conditioned volume temperature, thus reducing unwanted heat gains and losses from the ducts.

  Wall Insulation: Prescriptive compliance now calls for “high-performance” walls.  For wood framed walls, this equates to R-21 batt + R-4 continuous sheathing (or equivalent), in most climate zones. 

  Third-party field verification:  No major changes from the 2013 Standards.

  Ventilation Cooling”:  The minimum cfm/floor area requirement was reduced for this prescriptive compliance requirement.

  Duct insulation:  In some climate zones, the prescriptive requirement is increasing from R-6 to R-8.

  Domestic Water Heater:  The “standard” system for prescriptive compliance is changing from a single 50 gallon or less gas-fired water heater (per dwelling unit) to a single gas-fired tankless water heater.  Storage water heaters may also comply with the prescriptive requirements when additional energy saving measures are included in the design.

  Solar ready” requirement:  No changes from the 2013 Standards.

 

Performance compliance:

 

  Solar photovoltaic credit:  After a limited introduction in the 2013 code, now all new single-family and multi-family buildings (except in coastal Southern California) can take a performance credit for the inclusion of solar electric systems.  This is a relatively simply credit, because it is based on the rated KW size of the array (i.e. an annual energy production estimate is not required).  To earn a PV credit, the KW capacity must meet a certain minimum threshold, which varies by the size of the building.  The performance credit varies based on climate zone and building size.  The “credit” is not large (and it does not increase for systems larger than the minimum size), so don’t expect that having a PV system will allow one to build a glass house.

 

Lighting Requirements:

 

  Indoor Lighting:  There are a couple of major changes: All lighting must be “high efficacy”. Therefore, there are no longer kitchen lighting power calculations, which were previously required for kitchens that included some incandescent lighting.  Also, with the exception of recessed can lights, luminaires may use screw-based bulbs, as long as the bulb is labeled as meeting Title 24 high efficacy requirements.  [The CEC believes that most screw-based luminaires will be equipped with LED lamps, and that most residents will continue to use LED lamps rather than change them to incandescent bulbs]

  Outdoor & Garage Lighting:  No major changes from the 2013 Standards.

* Low-rise is three habitable stories or less above grade

 

 

return to top of page

 

 

BUILDING ALTERATIONS & ADDITIONS

 

NONRESIDENTIAL, HIGH-RISE RESIDENTIAL & HOTEL/MOTEL

ALTERATIONS:  In existing conditioned buildings or spaces, changing the envelope (e.g. fenestration, roofing, etc.), changing or adding mechanical systems, and adding new indoor light fixtures each “trigger” Title 24 compliance requirements for that system or component.  Under the prescriptive approach, adding new glazing area is subject to both glazing area restrictions and energy efficiency requirements.    

Converting an unconditioned space into “conditioned” space, by adding space heating and/or space cooling, triggers Title 24 compliance for that space’s envelope, mechanical and lighting.  Such a space is considered an “addition”, and therefore must meet requirements for new construction.  Adding lighting to unconditioned enclosed spaces, and to applicable outdoor spaces, also triggers Title 24 lighting efficiency requirements.

As initiated under the ’13 energy code, under the ’16 code’s prescriptive envelope compliance approach, no trade-offs may be made between different altered components.  Instead, all new/altered envelope components are measured against the prescriptive efficiency requirements for that component (which for new insulation and new glazing are somewhat less stringent than the requirements for new construction).  The energy code never imposes energy requirements on existing envelope components of existing conditioned spaces.

UPGRADE CREDIT:  Under the performance approach, “credit” towards compliance accrues only to the extent that the energy efficiency improvement exceeds prescriptive minimum efficiency requirements.

ADDITIONS:  Nonresidential building additions (construction that includes new envelope, floor area and volume) are treated similarly to stand-alone new buildings. 

 

For more detailed information about nonresidential alterations and additions, see Description: Description: http://www.energy.ca.gov/cecimages/pdficon_small.gif Nonresidential Alterations & Additions or contact Farber Energy Design.

 

LOW-RISE RESIDENTIAL

ALTERATIONS:  Changing the envelope (e.g. fenestration, roofing, etc.), changing and adding HVAC equipment, and installing new light fixtures each “trigger” Title 24 compliance requirements for that system or component.  Under the prescriptive approach, adding new glazing area is subject to both glazing area restrictions and energy efficiency requirements.  New HVAC equipment triggers several requirements regarding both the conditioning equipment and the air distribution system (for fan-forced central systems), including mandatory HERS tests.  New lighting in existing homes must meet the same efficacy and control requirements that new construction lighting are subject to.  Changing any equipment that is subject to Title 24 mandatory measures must meet their applicable energy 24 requirements (e.g. water heaters, swimming pool pumps, fireplaces, etc).

ADDITIONS:  Residential additions (new heated floor area and volume) must meet most of the envelope, space conditioning, water heating and lighting efficiency requirements that new residential construction is subject to.  While additions up to 700 sq. ft. floor area are only subject to the mandatory minimum roof insulation requirement, additions of any size are subject to the same “high-performance” wall insulation requirements as for new residential buildings.  However, exterior walls that line up with existing exterior walls are not required to be any thicker than the existing walls.  No changes to fenestration requirements as compared to the 2013 Standards.

UPGRADE CREDIT:  For both alterations and additions, when improvements are made that improve the building’s energy efficiency, performance approach “credit” towards compliance only counts to the extent that the improvement exceeds prescriptive minimum efficiency requirements. Exception:  If a HERS Rater performs an existing condition review prior to permit document submittal, then substandard existing conditions (such as single-pane windows and uninsulated walls) that are improved will receive the full value of the improvement as credit towards performance approach compliance. 

 

 

MODELING FENESTRATION ENERGY EFFICIENCY

 

A very important aspect of the standards is the methodology used to model fenestration.  Since the 2001 Standards, Title 24 has required that the modeled SHGC and U-factor for fenestration, whether factory-assembled or “site-built” (storefront and curtainwall), be derived from NFRC certified values in order to meet the prescriptive energy efficiency requirements.  For more information about this and other aspects of fenestration and the energy standards, see the fenestration page of this web site.

 

return to top of page