LEDs for Indoor Scott Riesebosch Chief Technology Officer

CCT – what is it and why is it important for indoor lighting? And why the extra C? CRI – what is it and why is it important? Are LED replacement lamps really a contender? Some reliability data points to consider

Colour Temperature (CT) Colour temperature refers to shades of white light, and is measured on the Planck blackbody radiator scale (Black Body Locus, BBL) This scale measures the colour of a blackbody radiator (an ideal device with perfect absorption and emission) at various Kelvin temperatures Example blackbody radiators at various color temperatures.

Correlated Color Temperature (CCT) Not all white light lies directly on the BBL CCT refers to the Plankian black-body radiator colour temperature (CT) that is closest to the colour of the white light source Examples of CCTsRelationship between CCT & CT

Correlated Colour Temperature Effects

Color Rendering Index (CRI) CRI is an objective standard used to judge how well a light source renders colours compared to a black-body radiator or daylight Incandescent bulbs are – by definition – equal to 100 Eight pastel colours are measured under the test light source CRI measures how much these colours are affected by the light source Note: LEDs have fully saturated colour and actually pay a mathematical penalty on the CRI system. Other standards for communicating colour are under investigation …

CRI of common light sources Typical Warm White LED Halogen MR Typical Cool White LED 100Incandescent 75-85Metal halide 79Daylight fluorescent tube 55Warm white fluorescent tube 25High pressure sodium < 18Low pressure sodium CRILight Source

LED replacement lamp performance Although there were a few exceptions, most of the lamps had color quality attributes that were appropriate for replacing halogen PAR lamps in most applications All of the LED PAR38 lamps tested offer substantial energy savings compared to halogen PAR38 lamps, and some are more efficacious than compact fluorescent or ceramic metal halide versions It is reasonable to conclude that LED PAR38 lamps are (at least in terms of performance) a viable option in most installations where PAR38 lamps are used Source: USDOE Caliper Program Summary Report 20 November 2012

LED replacement lamp performance Many of the Series 16 products would be an effective energy- saving alternative to incandescent BR30 or R30 lamps. Further, the efficacy and color characteristics are similar to or better than directional CFL lamps Adding other factors such as dimmability and longer rated lifetime makes LED BR30/R30 lamps the best solution for replacing inefficient and soon-to-be regulated incandescent BR30 and R30 lamps Source: USDOE Caliper Program Summary Report 16 July 2012

LED replacement lamp ROI Can be under one year in applications of high usage, and under 2 years in many applications Well suited to applications where maintenance cost is high Generally warranty is considerably longer than ROI Cost of ownership is a slam dunk in most applications

How much does it cost to change a light bulb?

Reliability – can they hold up? Plenty of reliability data now available Advances in material science and deeper understanding of failure modes that affect long term lumen maintenance and colour shift over time Energy Star program requires 6,000 hours of testing at elevated temperatures LED MR16 test lamps running continuously since August 2008

Reliability – can they hold up?

Over 44,000 hours later…

Thank you