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Monday, 23 November 2015 00:00

Energy Efficient Light Bulbs

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      Many people must have heard about energy efficient light bulbs but what they may not know is that there are different types of energy efficient bulbs. There are two main types of energy efficient light bulbs: compact florescent light (CFL) bulbs and light emitting diode (LED) light bulbs. Those that have heard of these are still confused as per the essential difference between them. Nigerians have started showing significant interest in energy conservation and the reason for this is not farfetched: the regulator of the Nigerian electricity industry has approved countless tariff increases in the last two years that left Nigerians groaning under huge electricity bills. Consequently, Nigerians are now more energy conscious and also pay more attention to the appliances they use and the methodologies that will lead to energy conservation as a means of reducing energy consumption that will ultimately lead to reduced bills. While energy efficient light bulbs result in energy conservation when compared to incandescent bulbs, certain types are more energy efficient than others. Available data indicates that the LEDs are more energy efficient than the CFLs.

     Available statistics show that in an average home, depending on the style of lighting, electric bulbs can be responsible for up to 25% of the home’s monthly electricity consumption. This is no surprise at all as many electricity consumers are oblivious of the ways in which different light bulbs consume energy.

This paper aims to shed light on the differences between the commonly used light bulbs, the Incandescent (yellow) bulb, the Compact Fluorescent Light (CFL) bulb and the Light Emitting Diode (LED) bulb, and the differences in their energy requirements.



The Incandescent bulbs are the most common and oldest type of light bulb. Due to the limitations in technology at the time of its invention, the bulb’s design makes it require much energy to operate: When electricity is applied, the current travels up through the rods and heats a curly piece of metal called a Filament, all enclosed in the transparent globe. It is this heated filament that glows to produce the light we see.

The Filament is made up of a metal called Tungsten. Tungsten is a metal that can withstand very high amount temperatures (up to 5,000 degs F or 2,760 degs C) which is the reason they are used to produce filaments. However, the heat produced from heating the filament is so high that about 90% of the heat is given off to its immediate environment. This high heat generated by the bulb is the reason it consumes a lot of energy.

The design of the bulb is such that the enormous heat produced by the filament does not burn out the filament immediately; they are thin at the bottom and wide and circular at the top (where the filament is housed). The space at the top allows the heat generated to spread out over a large surface area. Also the gas (Argon) present in the bulb assists in distributing heat uniformly. Argon is an inert gas and hence retards the process of oxidation of the filament. Inert gases (Group 18 elements on the Periodic table) are gases that do not undergo chemical reactions under a set of conditions, thus they are generally used to avoid unwanted chemical reactions. This ostensibly gives the bulb longevity as it takes longer for the filament to oxidise and burn-out.



The CFLs have been in existence since the 1940s though they looked slightly different from the spiral ones now commonly in use. They were made to be thin and straight, and were often called “fluorescent light” or “fluorescent tubes”. However, the advent of the cock-screw light sockets made the need for bulbs that fit into the new sockets sacrosanct, hence the birth of the spiral shaped Compact Fluorescent Lights (or CFLs).

CFLs are “gas discharge” lamps. This means that light is generated by sending an electrical charge through an ironized gas. In a CFL, an electric current is driven through a tube containing argon gas and a small amount of mercury vapour when the light is switched on. This electric charge excites the mercury vapour, causing it to produce an ultra-violet light (invisible to the eyes) which in turn excites a fluorescent coating (called Phosphor) on the inside of the tube, which then emits the visible light.

CLFs use a little more energy when they are first turned on, but once the electricity starts flowing, they use about 70% less energy compared to the Incandescent. The huge difference in energy consumption between the two bulbs is as a result of the absence of the heat due to the Tungsten filament. Therefore CFLs can be held even while they are on, and they last up to eight times longer than the Incandescent bulbs. The higher the wattage of the CFL bulb the higher the energy used. For instance a 20 watt CFL will feel warmer to touch than a 12watt equivalent.



LEDs are composed of a number of light emitting diodes enclosed together to produce a bright white light. This is obviously because a single diode will not provide the required intensity of light (Lumens) needed for use in homes or offices. To achieve this, the LED manufacturers imitated the structure of the Incandescent bulbs, giving the LED bulb a rounded top to enable proper distribution of the light produced. Also, thin fins were installed on the stem of the bulbs to allow some heat dissipation, thus reducing the strain on the semiconductors.

Most diodes are made from semiconductor materials like silicon and germanium.

The technology involved here is the agglomeration of tiny light bulbs that are fitted onto a circuit, but these light bulbs do not use a filament. The light is produced by the movement of electrons in the semiconductor material. Since they do not use filaments that will always burn out, the LEDs can last for a very long time.

The technology of the LEDs enabled the creation of one of the world’s most energy efficient light bulbs. By making use of LEDs, you consume 85% less energy than the Incandescent bulbs. However because of the components that make up the LED bulbs, they are more expensive than the CFLs and the Incandescent.

LEDs are used widely used in many electronic devices aside light bulbs including digital time pieces, Traffic Lights, Electronic Bill boards, Televisions, among others.








High energy consumption

Low energy consumption

Lower energy consumption


Susceptible to damage from heat

Not likely to get damaged from heat

Never damaged from heat






Short life span

Long life span

Very long life span


Read 1757 times Last modified on Monday, 23 November 2015 15:51

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