Has the day of LED lighting arrived?

Notes for Ecobuild 2011, London

Jill Entwistle, a lighting designer, reported at Ecobuild that LED lighting had improved exponentially in quality over the last 2 years.

 Mike Simpson, Philips Lighting provided some hard facts:

  • 60W filament replaced with 12W LED
  • 50W tungsten halogen replaced with 10W LED
  • 26W compact fluorescent replaced with 17W LED (with 3 times the life expectancy)

 A number of lighting designers (Lee Prince, Dominic Meyrick, Richard Bolt) showed slides at Ecobuild demonstrating how, using LED, you can have a luxurious lighting design and save energy e.g. backlit LED sheers, LED strips instead of tungsten.

 Achieved examples included:

 Hotel: Average lm/cw of 55, with full load of 9.8W/m2. Actual levels ranged from 3-6W/m2 in daylight hours to 5-6W in non-daylight hours.

 Office refurbishment: mixed CFT and fluorescent to LED change reduced connected load by 44%. 33W/m2 reduced to 18.7W/m2.

 External lighting of cathedral: 28kW load reduced to 14.5kW with LED and reduced light spill.

 External lighting of Tower Bridge: LED lighting trialled using 4kW compared to the current 200kW flood lighting.

 However, there were also warnings that LED was not the answer to everything. Some warnings were raised, including:

  • Can suffer from glare
  • They do get hot. Quoted output is at lower temperatures than actual operating temperatures. 20% loss in lumens at 100C.
  • Life varies by load.
  • Life predictions are not proven.
  • Colour rendering not as predictable and can appear too blue.
  • Still expensive to buy.

 Predictions:

  • External lighting will go LED.
  • LED needs to be used differently not just as replacement. Design is key.
  • Similar to tungsten halogen downlights but saving energy and maintenance so will replace.
  • Right light, right place, right time still needed.

 LED lighting has been added to the list of default lighting within the Simplified Building Energy Model for 2010 BRs. However, the default inferred energy efficiency is less than T5 or T8 fluorescent.

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