I was fortunate to be able to spend the weekend visiting the Solar Decathlon houses on the Mall in Washington, D.C. (see the Solar Decathlon website and Amber’s last blog article “Curious” About Sustainable Design?).
Miserable weather meant that the houses weren’t generating much electricity, but the energy produced by the students attracted many people like me willing to stand in long lines in the rain and mud to see their work. I was impressed by the sheer immensity of what the students had accomplished (none more so than the Lam-sponsored Team Boston!) and the many ways in which each team solved the same sets of design problems. It was fascinating to see how they balanced the tensions between having to make a highly efficient house that also functions well, would be a nice place to live in, and is beautiful. You could see the compromises: the house that was super-insulated but didn’t have many windows, or the house with large south-facing windows but no architecturally integrated shading to block the summer sun (perhaps because it would have violated the purity of the architecture) – or the house that kept the lighting energy so low that the lighting quality suffered.
But the thing that struck me most about the competition was not something I saw on the Mall, but an entry in Thursday’s Daily Journal on the Solar Decathlon website. In describing the winners of the Lighting Design competition, it said: “A Minnesota team member commented that their goal was to use only 500 watts (or the equivalent of five incandescent light bulbs) to light the entire house”. Now, I appreciate the attempt to make the information accessible to the average consumer, but this comment is so telling about the incorrect way that the world considers lighting energy efficiency.
The Solar Decathlon is a contest that measures (among many things) energy-efficiency, not total watts. Energy is Watts x Time (see my blog article Fight the Power! ) So I could have 2,000 watts of total lighting in my Solar Decathlon house, but if I only needed to turn some of it on for a small amount of time each day, I could use less energy than a house with 200 watts of total lighting that had to have all the lights on most of the time. If they only measured watts at the Solar Decathlon, then all they’d need to do is hook up the houses to a meter, make them turn on every system and appliance, and the house with the lowest wattage would be the winner. Well, that would be easy – but it would be dumb. So why, then, do we talk about lighting performance this way?!
So there I was on Saturday in one of the houses and a charming student tells us that all their lighting uses only 200 watts. Sigh. And then later that afternoon, in another house a student tells us how their LED fixtures use just 3 watts each. Arrgghh. So OK, we’ve done a bad job educating our students about how to measure lighting energy efficiency, but this also brings up another timely issue: lighting quality. What if you only use 200 watts but lighting quality is poor?
And then, as expected, the LEDs were everywhere along with the hype. Several houses proclaimed that all their lighting was LED, as if just saying that indicates some special level of energy efficiency. And of course, as we were told at one house, “LEDs are seven times more efficient than an incandescent light”, when realistically they are maybe half that. Where do they get this stuff? And it’s not just efficiency misinformation, but the lighting quality issue too. Far too often, the LED sources that I observed were glary and had a ghoulish cool color. If the Solar Decathlon is a predictor of trends in residential lighting, then we might conclude that we have a lot of glare in our future.
Another comment I overheard that I thought was telling went something like this, from a gentleman standing below one of those glary LED accent lights: “Gee, if we could only get LEDs that were good for ambient lighting”. I almost went up to him and said, “You have a much better source already – linear fluorescent – twice as efficacious as LED, and much less expensive.” But I kept my mouth shut and wandered out into the rain and mud thinking that we Lighting Designers have to do a much better job educating students and the world about how to achieve true lighting energy efficiency and lighting quality.
Photos Credit: Glenn Heinmiller / Lam Partners Inc