We could not survive without artificial light, however the use of certain types of lighting does present some environmental issues involving energy efficiency and light pollution – one of the three main greenhouse gases, carbon dioxide (co2) is emitted whenever a light is turned on.
Traditional incandescent light bulbs use 90% of their energy emitting heat. Modern, energy efficient light bulbs use up to 70% less electricity than traditional types, last around ten times longer and emit far less heat.
Although they are more expensive than traditional types, energy efficient light-bulbs save the user money on electricity bills over time and they emit less co2
Different rooms require different forms of lighting. For example, the kitchen light is often left on for long periods of time and fluorescent lighting is a popular choice here because of its efficiency.
In the living room the focus is more on decoration and setting a comfortable mood and in the bedroom there is no obvious need for strong lighting but energy efficient bulbs are still appropriate.
Though energy efficient light bulbs are initially more expensive than their traditional counterparts, they will pay for themselves over time, as they reduce the energy consumption by as much as 70%, and can last up to 13 times longer than ordinary bulbs, with a typical lifespan of 10,000 hours.
Compact Fluorescent Bulbs
Unlike incandescent bulbs which use a filament, compact fluorescent light bulbs give off light when a mixture of three phosphors are exposed to ultraviolet light from mercury atoms.
These bulbs provide as much light as regular incandescent bulbs while using just one-fourth the energy. For example, a 15-watt compact fluorescent bulb yields the same amount of light as a 60-watt incandescent bulb. Compact fluorescent bulbs last about 10,000 hours — 10 times longer than incandescent bulbs.
There are trace amounts of mercury in compact fluorescent light bulbs. For the home user, this presents no problems so long as used bulbs are disposed of properly. These bulbs are definitely beneficial for the environment.
If every home replaced one bulb with a compact fluorescent light bulb, it would be equivalent to taking one million cars off the road.
A halogen bulb still has a tungsten filament inside, as do traditional bulbs, but with a difference. Inside these bulbs there is a halogen gas (almost always iodine) mixed in with the argon or krypton. This gas reacts with the vaporised tungsten that collects on the glass to form chemical compounds called metal halides.
These then leave the inner surface of the bulb in a constant recycling process and return to near the filament where the increased heat breaks down the halide into its constituent parts. The tungsten molecules are now given to return to the filament, and the iodine molecules are free again to join up with any more ejected tungsten.
This is known as the halogen cycle. Halogen bulbs cost more, but have a lifetime of up to triple a normal light bulb of the same wattage, and at the same time be anything up to a fifth more efficient at producing light.