Singapore, 11th September 2012
Probably a little over a year ago I was still pretty sceptical about the performance of LED technology in outdoor flood lighting applications, but I have to admit the technology has caught up with me! As we are considering lighting options for the façade lighting of a Foster designed prestigious building, we have been consulting with leading floodlighting manufacturers to get a feel of what is currently possible and the technical and electrical parameters that come with it as a result. Here are some amazing figures just for reference. It varies from manufacturer to manufacturer so my reference is just a general reflection averaged through the various manufacturer options I have been assessing.
In traditional floodlighting (still valid today) I would use either a 1KW or a 2 KW floodlight which typically would produce about 15 to 20,000 cd per 1000 lumens. Amazingly today’s LED technology is able to produce floodlights with performances of up to 30,000 cd per 1000 lumens with amazingly tight beams and glare control! But as the lumens per watt for LED technology are hitting past the 100 lm/W we end up with a 250W LED floodlight easily capable of producing a lighting performance comparable to a 2 KW metal halide fixture!!! In one of the options I looked at 30 pieces of 2KW MH floodlights could be replaced by 24 pieces of 290W LED floodlights, or 7KW instead of 60KW, that is massive! But it comes with a massive price tag as well, close to 5 times more expensive.
Of course over life there is the ease of (practically no) maintenance and the energy saving to discount and that is where many of our dear manufacturers twist the figures a bit to make the LED proposition more cost attractive. Metal Halide is compared with only a 5000 hour lifespan, with the lifespan dictated by a 50% failure rate, to LED’s 50 to 70,000 hours, with the lifespan here dictated by a 70% lumen depreciation threshold. Not really an apple to apple comparison….
But having said that and price and ROI aside, the technology progress has been amazing without doubt. Add to that the amazingly compact dimensions that can be achieved and we can truly say that LED floodlighting is coming of age!
Light Watch 3-138: Conventional floodlighting using metal halide floodlights (Petronas Twin Towers, KL) compared to LED technology (Aqua Building, Chicago)