Wednesday, June 3, 2009

Solar And Other Exterior Lighting

How to be safe and save energy


A few well-placed outdoor lights can make you feel more secure at night. They can help the pizza guy find your door and keep you from tripping over the cat when you're taking out the garbage.
Solar and Other Exterior Lighting

Poorly used lights, on the other hand, can rob your neighbors of a good night's sleep, disrupt wildlife, and waste precious energy and hard-earned cash. They may even be harmful to human health. Light at night can interfere with the production of melatonin, a hormone that inhibits the development of tumors. So researchers suspect exposure to well-lit nights may increase a person's risk of cancer.

Light has even become a form of pollution that extends far beyond our neighborhoods. Shining upward, it causes moisture and particles in the air to glow. This "sky glow" obscures stars and planets, interfering with astronomers' work and keeping people living in urban and suburban areas from experiencing the wonder of a truly dark sky.

Fortunately it's not so hard to keep those rays where they belong. Whether you want to light a walkway, driveway, entry door, balcony, deck, or patio, here are some ways to make your effort effective and efficient.



Top Tips


At home

  • Investigate. Go outside on a dark night and take a good look at your exterior lights. Are any of them unshaded--either bare bulbs or bulbs behind clear glass shades? Do any of the light fixtures point light up toward the sky, or let light stray horizontally onto a neighbor's property?

  • Use outdoor lights only when and where needed. Don't go overboard with the number of fixtures you install, and don't leave them on all night. Use timers and motion sensors to limit the amount of time they are on.

  • Use the least amount of light needed, not the most. Overlighting is a nuisance to your neighbors and a waste of your money. Use the lowest wattage bulbs to get the job done.

  • Light from the top down, not from the bottom up. Lights that point up to the sky waste energy, create glare, and obscure views of the night sky.

  • Shield. Add shields to bare floodlights, and replace clear shades with diffusing shades.


When shopping, look for

  • Energy-saving bulbs. Replace higher-wattage bulbs with low-wattage CFLs. Keep in mind that you're not likely reading or knitting outdoors. So it's appropriate to use fewer watts than you would inside. Compact fluorescents or LEDs are more energy efficient than incandescent and halogen bulbs.

  • Shielded fixtures. You want to send light downward, not up into the sky or horizontally into your neighbor's window. So use shielded fixtures. The International Dark-Sky Association has a seal of approval program for shielded outdoor lighting fixtures.

  • Weather worthiness. When choosing a CFL, check the label to make sure it's meant for outdoor lighting. Bulbs are available that can be used in temperatures as low as -10°F and as high as 120°F. At the cold end of the scale, they may take longer to reach full brightness.

  • Solar power. Solar-powered LED pathway lights are handy for remote areas where it would be expensive to run wiring. A small photovoltaic panel on the light fixture generates electricity when exposed to sunlight. The electricity is stored in an internal battery to power the light bulb after dark. Solar lights usually use LED bulbs, although some use very low wattage CFLs that put out a bit more light. Most solar lights are dim-they put out just enough light to allow you to follow the walkway without tripping. But they're handy because they don't require any wiring or installation know-how. Performance varies; shop around and make sure you buy from a store with a good return policy.Many solar lighting products come mounted on a stake that you push into the ground; others have brackets for wall mounting. Most products need at least four hours of direct sunlight to power the light for six to ten hours that night, but some may need even more. Other solar-lighting products include motion-sensing security lights and solar stepping stones.




Other Considerations


Low-voltage lighting is popular for walkways, landscaping, steps, and other areas. It can be professionally installed, or kits are available for DIYers. These systems typically use low-wattage halogen lights and run on 12 volts instead of the regular 120-volt household current, making them very safe--there's no concern about electric shocks. The wiring can either be buried or laid on the ground and covered with mulch.



Benefits...


...to you
Low-contrast lighting is better for security purposes than bright lights that create obscuring glare, dark spots, and shadows. Some research also indicates that outdoor lights on motion sensors do a better job of deterring crime than lights that are on all the time.

...to your wallet
Shielded fixtures don't cost any more than unshielded fixtures. Energy-efficient CFLs also keep your outdoor lighting costs down, and they are available for a pittance--as little as 50 cents a bulb at many discount retailers. In the nation as a whole, badly designed outdoor lighting results in $4.5 billion a year in wasted electricity. If you have 5 incandescent light bulbs outside your home, your share of that waste is about $150 per year. Switch to CFLs and start saving immediately.

..to the Earth
In addition to disrupting melatonin production in humans, electric lighting at night can interfere with the mating, foraging, migration, and predation behaviors in other species, which can potentially disrupt entire ecosystems. Even plants may not be immune from the effects of lighting up the night. According to some studies, trees that are lit all night may not respond appropriately to signals of winter dormancy. And don't forget the carbon emissions, which contribute to global warming.



Common Mistakes


Burning gas lamps. Decorative natural gas lamps look romantic but they're big polluters. According to the U.S. Department of Energy, burning eight lamps all year uses as much natural gas as it takes to heat an average size home for a full winter.



Getting Started


If you are in the market for a shielded fixture, check out the International Dark-Sky Association's seal-of-approval program.



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