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  • Sci. & Tech.
    Environment: case for low energy light bulbs

    GUARDIAN NEWS SERVICE

    By Duncan Clark

    still using those old-fashioned energy-guzzling lightbulbs? Then it's time to do the bright thing and change. Duncan Clark explains why eco lighting doesn't have to mean a gloomy slow burn

    1 People always moan that low-energy bulbs are dim when you first switch them on. With older bulbs, that was certainly the case, and many people still have these. But technology has improved: modern low-energy bulbs fire up instantly and typically reach their full brightness within a few seconds (except when the room is really cold - then it takes longer).

    2 Each time you replace an old-fashioned energy-guzzling bulb with an equivalently bright low-energy version you slash the associated CO2 emissions by about 80%. In addition, over the five or six years that it will typically last, a single low-energy bulb can save you more than $100 in energy bills. If you buy the bulb for $2, that's a return of 5,000%.

    3 A decade ago, low-energy bulbs produced a harsh light. Today, that's not the case. When the magazine Popular Mechanics asked people to assess the light quality from ten bulbs, without telling them which was which, all nine low-energy bulbs tested scored more highly - for faces and reading as well as general ambience - than the traditional incandescent bulb used as a benchmark.

    4 With an old-style 100W bulb, you're effectively switching on a 20W light source and an 80W electric heater. In warm months, that heat is simply wasted. Even worse, it can increase the demand for fans or air conditioning, thereby wasting even more power. Green lightbulbs, by contrast, convert nearly all the power they consume into light, rather than heat.

    5 There are many types of low-energy bulbs. Most are CFLs - compact fluorescent lights - which apply electricity to a tube of gas. This creates UV light inside the bulb, which in turn illuminates the bulb's inner-skin of white phosphor to create visible light.

    6 And they come in all shapes and sizes, including globes and candles as well as the less attractive tubular designs.

    7 What's black, filthy and weighs as much as a 50kgs sack of cement? Answer: the coal required to illuminate a single 100W lightbulb for its 1,000-hour working life. In other words, every time you place an old-fashioned bulb in your shopping basket, you're indirectly shovelling 50kgs of the most polluting fossil fuel into a power-station furnace.

    8 LEDs are the bulbs of the future. They are even more efficient than CFLs, but most at present don't produce much light - great for night lights and accent lighting, but not a substitute for regular bulbs.

    9 What about halogens? Widely used for recessed downlights and tracked spots, these are more efficient than regular incandescent bulbs, but this benefit is often offset by the number of bulbs installed. Many modern homes have five or more downlighters in a room, and tracked spots often include three or more bulbs in each fitting.

    10 Ever heard of dichroic halogen bulbs? These offer the familiar halogen brightness, sparkle and dimmability but last much longer and use up to 30% less power. Another option are mini-CFLs designed to fit within a halogen enclosure. These are less sparkly and may not be dimmable, but they offer plenty of light for a minimal amount of energy. Both options cost more than regular halogens, but they also last many times longer.

    11 Old-style incandescent globes are being phased out and in Europe, at some stage, the EU will also pass mandatory rules outlawing the least efficient bulbs.

    12 When this phase-out was announced, there were protests about the supposed downsides of low-energy alternatives. Some commentators pointed out that CFLs contain mercury, a toxic metal. In fact, there's less mercury inside each bulb than would be emitted directly into the atmosphere by a coal-fired power station producing the extra electricity required by a traditional bulb. So using CFLs can theoretically reduce atmospheric mercury levels.

    13 That said, it's true that CFLs need to be disposed of properly (most bulb retailers and municipal dumps will take them). In the rare case of a bulb breaking in the home, open the window for a while and, as a precaution, wear rubber gloves when sweeping up the fragments.

    14 Another frequently heard whinge is that low-energy bulbs can't use dimmer switches. This isn't true, as there are already various brands of green bulbs compatible with dimmers. Again, they cost more than regular bulbs, but if you factor in energy consumption, each bulb you purchase will represent a massive saving.

    15 Switching to low-energy bulbs is a no-brainer. But what about the argument that anything anybody does to be green will be offset by the growth of China? In fact, not only are emissions per person in China still much lower than in the UK, for example, the Chinese government is also promoting energy saving. In April this year it unveiled a massive subsidy scheme to encourage the use of low-energy lightbulbs. The Chinese also produce most of the world's low-energy bulbs. The least we can do is use them...


    Sci. & Tech.






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