Lighting Efficiency

The new symbol of conspicuous consumption is the LED light bulb. LED bulbs make sense when replacement is difficult and expensive; for example, street lights. However, where changing bulbs requires only a stepladder, 4 foot T8 fluorescent tube fixtures are less expensive, less polluting, and more energy efficient.

On sale at the nearby Home Depot: Cree "65W" (650 lumen, 9.5W actual) LED incandescent bulb replacements for $15.

For comparison, an electronic ballast T8 fixture costs more than a "free" incandescent socket, but once it is in place, the ballast can last for decades and efficiently delivers power to the fluorescent tubes. Electronic ballast is instant-on and flicker free, and with bluetooth controllers (admittedly more expensive), the ballast can be dimmed and computer controlled.

The four foot tubes themselves can be had for $72 for a box of 36. Slightly more expensive Philips Alto bulbs are very low mercury - and the tubes can be recycled and the mercury recovered. Perhaps that is possible for LED bulbs, but I don't know where or how. F32T8 bulbs range from 25 to 32 watts, and their efficiency depends on the color spectrum: warm (yellowish) lights are less efficient, but more pleasing to some than cold (bluish) light. Not sure where those terms come from, since the color temperature of "warm" lights is 3000K, while the color temperature of "cold" lights is 5000K. Oh well.

But what about efficiency? Here are three example Philips F32T8 tubes from the Platt Electric website, compared to the Cree at Home Depot:

My experience with tube lifetimes - I've run some T8's for over a decade. The watts numbers given for the bulbs seem to be "fixture" watts rather than bulb watts; when I run these bulbs in fixtures connected through power meters, I see those kinds of wattages.

Are LEDs "Green"? Well, the materials are sourced in China, not because the minerals aren't found in the US, but because the mines they could come from have been shut down. The rare earths used in LED bulbs are co-located with thorium and other radioactives, and the tailings and runoff from mining are considered too polluting in the US. Perhaps polluting the Pacific Ocean from the other side, and risking Chinese lives, is OK? I don't think so, but I am not hip'n'withit, just a geek who uses calculators rather than slogans.