Our friends at the U.S. DOE Solid-State Lighting group just released a new study called the “Residential Lighting End-Use Consumption Study“.
I’ll get to the punchline right away: A lamp in the average U.S. household typically runs only 1.6 hours a day.
1.6 hours????? That equals a whopping 584 hours per year.
So I’ll do the basic L70 lifetime calcs for you:
10,000 hours = 17.1 years
25,000 hours = 42.8 years
50,000 hours = 85.6 years
However, the DOE also studied the total energy consumption: The national average wattage for residential lamps is 47.7 W and the national average for total lighting electricity consumption is just over 1,700 kWh per home. So even though the lamps aren’t individually operating all that much, the aggregate energy usage is large, especially considering the national total. So driving adoption of energy efficient lamps is still a critical priority.
But the question must be raised: Do we need super-incredibly-durable-lasts-a-bazilllion-hours LED lamps for cheap consumer applications? Probably not. Maury Wright at LEDsMagazine just authored a commentary piece asking the same question. But my concern is this: If we shorten lamp lifetimes, how do mitigate the tragic environmental impact of all these electronics that will ultimately enter the waste stream?
In my presentation at the recent U.S. DOE SSL Manufacturing R+D conference in Boston, I raised the point that sponsoring R+D awards into “deep-green” sustainability for LED lighting products might lead to radical savings in total-life cycle cost, which ultimately would further drive LED lamp adoption rates (my slides are available here). Incredibly high source efficacy is reducing the thermal load to almost negligible impact, potentially allowing the integration of biodegradable materials into key components of light fixtures. Miniaturization of driver electronics reduces the quantity and total mass of non-recyclable components. Creative methods such as bonding LEDs to paper might open up extremely low-cost manufacturing techniques.
A big unknown is the flammability requirements of safety standards such as UL: Will they recognize the potential change and start to adapt the safety standards?
In an upcoming issue of LEDsMagazine, I’ve authored an op-ed piece summarizing my challenge to the DOE. I’ll post it here when it the issue comes out.