How Do Light Bulbs Work?

How Do Light Bulbs Work?

Choosing the right light bulb can be one of the easiest ways to conserve energy in your home, but it can also be a pretty confusing task. It used to be that we all had to buy the same egg-shaped light bulbs, but the search for energy-efficient lighting has led to a range of new options crowding local hardware stores. To help you decides what’s best for your home, we’ve put together this guide to shopping for energy efficient lighting.

Incandescent bulbs

When most of us think of light bulbs we think of traditional incandescents. Thomas Edison is credited with developing the incandescent bulb in the 1890s, and while advancements have been made in materials and manufacturing, the basic design remains the same today: a filament, usually made from the metal tungsten, is heated in a vacuum until it glows. While cheap to manufacture, incandescent lights have one glaring flaw: they are ridiculously inefficient. Only about 10% of the energy that goes into a traditional bulb gets turned into light; the rest is released as heat (anybody who’s tried to change a recently burned out light barehanded will know how true this is!). Many countries, including Brazil, Australia, the U.S., and most of Europe, have started phasing out incandescent bulbs with the goal of promoting the development and use of more energy-efficient types of lighting.

Halogen bulbs

Halogen lamps are a specific type of incandescent bulb that contain a halogen gas that interacts with the tungsten filament to prolong the life of the bulb. Halogen lighting is 10-20% more efficient than regular incandescents and will last longer, but you should make sure that wherever they are installed is properly ventilated because they can also produce a lot more heat.

Fluorescent bulbs

Fluorescent bulbs – the long tubes we’ve all seen in schools and office buildings – were developed in the 1920s and work by bouncing electrons around in a tube filled with mercury gas. The energy this produces will then light up the fluorescent coating on the glass. (Black lights and tanning beds work the same way, but have a different coating on the tube). They are more expensive than incandescent bulbs but are also much more efficient and will last longer. One of the biggest problems with fluorescent bulbs, though, is the toxic mercury they contain, which makes environmentally-responsible disposal difficult. Fortunately, fluorescent bulbs can now be recycled and the mercury reused in new lamps and kept out of landfills. In fact, most cities actually require that fluorescent bulbs not be thrown out with the regular trash.

Compact fluorescent bulbs
CFL Light Bulb

CFL Light Bulb

Until recently the benefits of fluorescent lighting were limited to large buildings, but the development of compact fluorescent lights (CFLs) has made it possible to bring this efficiency home. CFLs operate just like larger fluorescent bulbs, but are the same size as an incandescent. Most are designed to fit into traditional light fixtures so you can upgrade to more efficient lighting without having to make any changes to your home. They use 20-30% of the energy incandescent lamps require and will last 10-15 times as long. As with larger fluorescent lights, CFLs should be recycled to ensure that hazardous chemicals stay out of the environment. Many city recycling programs now accept CFLs as do large retailers like Home Depot, Ikea, and Lowe’s.

LEDs
LED Holiday Lights

LED Holiday Lights

Light-emitting diodes (LEDs) work by passing an electric current through a semiconductor which releases energy in the form of light. This style of bulb has been used for small indicator lights (think of the flashing lights on your computer or remote control) since the 1960s, but advances in technology have made them useful in other areas as well. You can now buy LED bulbs that will fit a traditional light socket and are more efficient and longer lasting than incandescents. LEDs can also easily made in a variety of colors by changing the semiconductor material, which makes them popular for applications like traffic signals and Christmas lights. And unlike CFLs they contain no hazardous materials, which means they are easier and safer to dispose of.

The bottom line

Skip incandescent bulbs in favor of more efficient CFLs or LEDs. While the price for both is still relatively high, their long life and low energy use make them a good investment.

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