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The use of electricity to create artificial light is a major consumer of energy. The replacement of conventional lighting equipment by energy-efficient lighting will therefore save a massive amount of energy. Commercially available energy-efficient lighting can save up to 75 percent of the energy currently used to light homes.
Upfront, these energy-efficient lighting solutions typically cost more than traditional lighting such as incandescent lights. However, the significant energy savings and longer bulb life is more than adequate to compensate for the initial outlay. As energy-efficient lighting technology becomes more popular, they will develop and become more cost-effective.
Types of Energy-Efficient Lighting
There are several types of energy-efficient lighting, including:
- Compact fluorescent lighting
- High efficient fluorescent lamps
- Light emitting diodes (LEDs)
Compact Fluorescent Lights
Compact fluorescent lights (CFL) are energy-efficient, long-lasting substitutes for incandescent light bulbs. Compact fluorescent lights are available in a number of configurations for different applications, including recessed, sconce, wall-mounted and ceiling-mounted fixtures. Compact fluorescent lights employ efficient fluorescent lamp technology and can be shaped like standard incandescent bulbs. These can directly replace incandescent bulbs without any modification being required to the existing fittings.
Incandescent light bulbs generate light by the flow of electricity through a tungsten filament causing it to heat to incandescence. 90% of the energy used is wasted as unnecessary heat. With prolonged use, the filaments eventually break, causing the lamp to burn out. This occurs typically at about a thousand hours.
Energy-saving incandescent lamps have been developed, which save about 25% of energy. All incandescent bulbs last about 1000 hours, with energy-saving varieties having a life of up to 3000 hours.
In contrast, compact fluorescent lamps use mercury vapor and a phosphor coating.While compact fluorescent light bulbs do cost more than incandescent bulbs initially, they can last for years without being replaced.
Compact fluorescent lamps are up to four times more energy-efficient than incandescent light bulbs. Compact fluorescent lamps use about 2/3 less energy than standard incandescent bulbs, while giving off the equivalent amount of light. They also last 6 to 10 times longer, with a life of about 10 000 hours. For example, an 18 watt compact fluorescent lamp provides the same light output as a 75 watt incandescent light bulb.
Buyers Guide to Compact Fluorescent Lights
When buying compact fluorescent lights to replace incandescent bulbs, compare the light output, or lumens, instead of watts. Watts is a term which is used to refer to the amount of energy used, not the amount of light generated. The table below shows the difference in energy usage between compact fluorescent lamps and incandescent lamps to generate the same amount of light.
Recent advances in fluorescent lamps and electronic ballasts have created the opportunity for significant energy savings when replacing any prior generation of fluorescent lighting. Linear fluorescent lighting systems can be upgraded by installing high performance T8 lamps and electronic ballasts in the existing fixtures or by installing new T5 or high performance T8 lighting fixtures.
High-efficiency or high-performance fluorescent lighting offers higher efficacy levels, longer lamp life, and longer warranties than their standard counterparts. High performance T8 systems are available at different wattages. High-performance T8 systems operate more efficiently than standard T8 systems. When selected carefully, these T8 systems can provide dramatic savings when compared with other fluorescent technologies.
High-efficiency fluorescent lighting can be installed in areas normally lit by standard fluorescent lights such as kitchens, laundry rooms, basements and garages.
Light Emitting Diodes
LEDs (Light Emitting Diodes) are small, solid light bulbs which are extremely energy-efficient and durable. They produce light directed in only one direction, and thus there is no need for diffusers or reflectors. This means most of the light generated leaves the fixture rather than being wasted in reflection.
They are expensive, but do not burn out or heat up, with a life cycle of 20 years. In contrast, incandescent bulbs waste 90% of the energy used on heat production, while for CFLs it is about 80%.
LEDs use up to 80% less energy than incandescent bulbs but may last for up to 25 000 hours. Thus the cost ratio for burning an incandescent, CFL or LED would be about 4.8:1.2:1. That is, using an incandescent bulb costs about five times as much as an LED, and about four times as much as a CFL.
Until recently, LEDs were limited to single-bulb use in applications such as instrument panels, electronics, pen lights and, more recently, strings of indoor and outdoor Christmas lights. With regard to decorative lights, LEDs are safer since they do not produce heat and are more resistant to breakage, being made of epoxy rather than glass. They are also easier to use without the fear of energy overload.
Recent improvements in manufacture have lowered the cost of LEDs, which has expanded their application. These bulbs are now available in clusters, from 2 to 36 bulbs, and are popular especially for battery powered items such as flashlights and headlamps. LEDs are also available in arrays which fit standard AC and DC receptacles, lamps, recessed and track lights. They are also being used to provide light for indoor agricultural production. Their efficiency and directional light production fits them for these applications.
This type of lighting relies on mercury vapor, metal halides and sodium at high pressure, with the efficiency increasing from first to last. Of course, mercury vapor, being the least efficient and the most toxic, has been phased out. The others produce brilliant light which is ideal for lighting outdoors areas.
Sources and Further Reading
This article was updated on 10th April, 2019.