What is Title 24?

California’s New Title 24 Makes Smart Lighting Standard

    The California Energy Commission recently updated its Title 24 Energy Efficiency Standards, improving what “up to code” means by 25 percent for residential buildings and 30 percent for commercial buildings. The new standards, which take effect January 1, 2014, introduce requirements for photosensors, occupancy sensors and multi-level lighting controls, both indoors and out, making adaptive lighting the new standard in California.

    Adaptive lighting—lighting that automatically dims or shuts off when it’s not needed—represents one of the largest near-term opportunities for energy savings, and its inclusion in the state’s building code marks vital progress. The California Energy Commission projects the non-residential standards alone will save the state 372 GWh every year. Hopefully, they will also pave the way for other states pursuing climate goals.

    California’s Title 24 building standards (along with its Title 20 efficiency regulations for appliances such as lamps and portable luminaires) help the state meet its energy and climate goals as laid out in several important pieces of legislation. These include California’s Global Warming Solutions Act (AB 32) and the Huffman Bill (AB 1109), which is aimed at reducing statewide lighting energy consumption well below 2007 levels by 2018. Most recently, Governor Brown’s Executive Order B-18-12 called for a 20% reduction in state energy purchases by 2018.

    The California Public Utilities Commission has also called for a 60% to 80% statewide reduction in electrical lighting consumption by 2020, in its Long Term Energy Efficiency Strategic Plan. This is on top of the goal to make all new residential construction net-zero by 2020, and commercial construction net-zero by 2030 . Since lighting currently accounts for nearly 30 percent of California’s electricity use, the extensive use of lighting controls is absolutely essential to meeting these net-zero goals.

    The most important change to the 2013 Title 24 standards, in terms of energy savings, is that many more retrofit projects will be required to meet the new-construction standards for lighting than under the 2008 code. Spaces in which less than 10 percent of the lighting is being changed out, or buildings in which fewer than 40 ballasts are being replaced are exempt, but otherwise all new lighting must meet not only the lighting power density (LPD) requirements, but also most of the controls requirements (including dimming).

Non-residential lighting changes

    One of the biggest changes to the lighting code for commercial buildings has to do with demand response (DR) capability. Under the current, 2008 code, DR capability is only required of retail buildings with sales floor areas over 50,000 square feet in size. When utilities issue a DR signal to these buildings, they must be capable of automatically reducing their lighting energy use to a level at least 15 percent below the building’s maximum lighting power.

    The new code will apply this DR requirement much more broadly, to all commercial buildings at least 10,000 square feet in size. As is the current case, designers are responsible for specifying controls that are compatible with the local utility’s DR protocol, and building operators are responsible for programming the lighting controls to automatically reduce lighting power consumption in response to DR signals. We anticipate that by 2014 utilities will be ready to engage more customers in energy-saving, cost-cutting DR programs.

    Daylighting control requirements have also been vastly expanded. Under the current non-residential building code, photosensor controls are only required in daylit spaces over 2500 square feet. The new code will require photocontrols in all interior daylit spaces with at least 120W of installed lighting power. This change in criteria, from sizeable areas to modest lighting power use, significantly expands the number of spaces required to use photocontrols, affecting virtually every office or commercial space with skylights or windows.

    For the first time, occupancy sensors and controls will be required in aisles and open areas within warehouses. The same goes for the book stacks of libraries and non-residential corridors and stairwells. Controls will have to reduce lighting power in these spaces by at least 50 percent during unoccupied periods. This particular aspect of the code is supported by numerous demonstrations conducted through California’s SPEED program and UC Davis’s California Lighting Technology Center (CLTC). Case studies of adaptive corridor lighting consistently measure energy savings of 50 percent or more.

    Under Title 24 today, buildings can keep approximately 15 percent of their full lighting capacity on overnight and during weekends, for security purposes. But under the new standards, areas of buildings that are not occupied 24/7 will no longer be able to leave the lights on. Modest allowances for egress lighting will remain, but, just like general lighting, egress lighting will have to be shut off outside occupied times. Only offices will be allowed to maintain lighting 24/7, but only along designated paths of egress, and at a reduced maximum of just 0.05 W per square foot (versus the 0.3 W per square foot allowed under the 2008 code).

    For the first time, lighting in parking garages, lots, and loading and unloading areas will also be required to have occupancy controls, with at least one step between 20 and 50 percent of full lighting power. Parking garages will be allowed a maximum of 500W per occupancy sensor. Case studies show that installing adaptive LED lighting in parking garages typically yields energy savings between 40 and 70 percent, depending on occupancy rates, light sources and other variables. As with corridors, this application for occupancy sensors and controls has been proven through SPEED demonstrations. Applied statewide, the new requirements for adaptive parking and garage lighting promise to yield significant energy savings. 

Outdoor Lighting Changes

    Outdoor lighting, too, will undergo some major changes. The 2008 code required all outdoor lighting to have either a photocontrol system or an automatic scheduling control system; the new code requires both. Motion sensor controls will be required, in addition to photocontrols and scheduling controls, for all outdoor lighting mounted 24 feet above the ground or lower and for any incandescent luminaires over 100 watts. Controls must reduce lighting power to each luminaire by at least 40 percent when the lights are not in use

    Changing the light pollution/trespass language, the new code will do away with the old cutoff system used for classifying outdoor luminaires up to 175W. Instead, luminaires up to 150W will have to comply with the IESNA’s BUG system for assessing backlight, uplight and glare. This brings the code language up to date for those lighting designers, specifiers and engineers who have already adopted the BUG rating system in their efforts to minimize light trespass, light pollution and glare hazards.

Residential lighting changes

    The changes to this aspect of the 2013 rules are not numerous, but they do introduce requirements for high-efficacy sources as well as vacancy sensors and controls in bathrooms, utility rooms and other spaces. The 2013 regulations also call for better skylights and high-performance windows. In addition to the changes to Title 24, California is currently developing a voluntary quality specification that will apply to LED replacement lamps. The standard is designed to help utility rebate programs and consumers identify which LEDs are capable of delivering good color rendering (90 CRI or above) and incandescent-like light quality (with a CCT of 2700K or 3000K) for a fraction of the energy use. 

Written by Professor Michael Siminovitch, Rosenfeld Chair in Energy Efficiency and director of the California Lighting Technology Center (CLTC) at the University of California, Davis. CLTC works closely with lighting industry leaders, utilities and regulatory agencies to develop, field-test and deploy energy-efficient lighting technologies. The center is currently preparing several Title 24 lighting design guides to help those ready to meet, or exceed, the new 2013 standards.