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Friday, November 24, 2006

The simplest step towards an energy efficient home

“I used to like to leave several lamps on in my house at night, because it made the house seem cozier and more cheerful,” says homeowner Anne Norwood. “If I left my bedroom to go make a snack, I’d leave the light on, not imagining one tiny light bulb could make much of a difference.”

Light bulbs are so small, after all. But if you leave ten bulbs burning for just one hour – quite likely in the average house – you’ve consumed one kwh of electricity. And if you live in an area fueled by coal power plants, such as the southeastern US, you’ve burned an entire pound of coal.

But what’s one pound of coal, in the scheme of things? Well, they add up quick. The average house in the coal-burning southeast burns 36 kwh per day, or 1100 per month. Nationwide, the monthly average is 850. When you consider that 8 pounds of mountainside are blown sky-high from the West Virginia mountains to obtain each kilowatt of coal-fueled energy, those numbers start looking pretty ugly.

Certainly, a lot of this can be attributed to heavy energy drawers, like air conditioners (2 kwh per hour) or water heaters (4 kwh per hour).1 But even though each incandescent light bulb uses just 0.1 kwh per hour, collectively, lights use as much as 40% of the electricity in many homes!

The good news is, by switching to compact fluorescent bulbs, you can leave your lights on just as much and burn only a fifth of the energy. A 20 watt CF bulb emits the same light as a 100 watt incandescent bulb, because it wastes less energy in the form of useless heat. Hold your hand over a lamp with an incandescent bulb. Feel the heat? CF bulbs emit almost no heat; instead, all that energy goes into making light.

Fluorescent bulbs also last much longer than incandescent bulbs. Replacing just ONE incandescent bulb with a CF will save you as much as $75 in replacement bulbs and energy bills. In the course of its lifetime, each CF bulb will prevent more than 450 pounds of emissions from a power plant. If every American home replaced just one incandescent light bulb with a compact fluorescent bulb, it would save enough energy to light more than 2.5 million homes for an entire year, and reduce greenhouse gas emissions equivalent to those of nearly 800,000 cars.

This seems incredible, but you do the math. Engineer Mike Stenhouse was doubtful as well, until he crunched the numbers himself. “It takes 100 pounds of coal to fuel a 100w incandescent light bulb for its 1200 hour life,” he calculates. “This is no urban legend. I did the math myself. So if you burn the bulb 4 hours a day, that is 100 pounds of coal a year per 100w light bulb. I have (no kidding) 84 light bulbs in my house.

“As a specific example,” he continues, “we have six 65w spotlights in our kitchen. They burn around 6 hours a day or around 2,000 hour a year. In the course of a year, it will cost me $24 to replace them and $66 to power them, $90 total. And it will use 280 pounds of coal to power them. I replaced them with 15w compact fluorescent spotlights with exactly the same light output. They cost 50% more a bulb than incandescent, but last 3 times longer. In the course of a year, it will cost me $12 to replace them and $15 to power them, $27 total. So I will save $63. And it will use only 65 pounds of coal to power them, a saving of 225 pounds. That is an 80% reduction in power, heat, and emissions. Not bad.”

Not bad at all. In fact, what’s to lose? The only down side, which is minor, is that fluorescent bulbs take about 30 seconds to come up to full light output. For this reason, CF bulbs are most useful in places where the lights are left on for a long time, but it doesn’t waste any more energy to turn them on and off than it does an incandescent bulb.

Changing your light bulbs is so ridiculously easy it’s hard to believe what a big difference it makes. This is one change you can make right here, right now, and feel good about, right away.

by Sara Kate Kneidel
Greener Magazine

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