The standards look at different rooms and areas of a house, and specify what types of lighting and controls should be used. For example, bedrooms must use either high-efficacy luminaires, or a manual-on occupancy sensor or a dimmer. High-efficacy ratings are shown below.
Ratings for high efficacy luminaires
Lamp power: less than 15 W Required lamp efficacy: 40 lm/W
Lamp power: 15-40 W Required lamp efficacy: 50 lm/W
Lamp power: more than 40 W Required lamp efficacy: 60 lm/W
High-efficacy luminaires are designed and built to operate only energy-efficient light sources, which includes fluorescent T8 lamps, compact fluorescent lamps (CFLs) with electronic ballasts, as well as high-intensity discharge (HID) lamps. LED fixtures are not mentioned in the standards – so where do they fit?
What about LEDs?
Determining whether LED fixtures meet the 2005 Title 24 definition of high-efficacy luminaires is complicated due to the variations from fixture to fixture.
Melissa Blevins of the California Lighting Technology Center says, "The complication lies in the wide variety of fixture power supplies, and how hard the LEDs are driven by the power supply. The issues associated with heat sinking affect the efficacy of all LED sources."
The concern surrounding the variability of individual LED luminaires with different operating conditions is magnified by the fact that LED efficacies today are so close to the cut-off point between high-efficacy and low-efficacy ratings for luminaires [see above].
"In the 2008 Title 24 revision, it is expected that the code will be modified to more clearly describe the testing requirements for LEDs relative to the high-efficacy requirements," says Blevins.
"In the meantime, it is recommended that manufacturers provide independent testing lab reports indicating that efficacy values for the LEDs meet the 2005 definition of high efficacy [see above] throughout its operational range." Crucially, this means that the LED modules should be tested under 25 °C ambient conditions in combination with the actual power supply that will be used in the field, in order to portray accurate and realistic lumen output and power consumption values.
The 2005 Title 24 standards can be obtained from the California Energy Commission's website. Also, the Residential Lighting Design Guide, explaining how builders can comply with the new regulations, can be found on the California Lighting Technology Center website.
Contact Melissa Blevins on email@example.com.