Everyone knows that different lamps require various amounts of energy during use. By the same token, it takes various amounts of energy to manufacture different lamps. For example, 1.29 kWh are required to produce a 75 W incandescent lamp, 1.89 kWh to make a 36 W fluorescent lamp, and 3.36 kWh to manufacture a 15 W energy-saving lamp. While all 3 lamps produce a comparable amount of light, they differ markedly in terms of service life. An incandescent lamp burns for 1,000 hours, a fluorescent lamp for 10,000 hours, and an energy-saving lamp has an operating life of 15,000 hours.

In order to determine which lamp puts in the best overall performance, it is necessary to create a standard basis of comparison. We have taken an energy-saving lamp as this standard unit of measurement. Such a lamp has an operating life equivalent to 15 incandescent lamps, or 1½ fluorescent lamps, as seen in the graphic below. The amount of energy required to produce all 3 lamps is relatively small compared to the amount of energy consumed during their use. Nevertheless, it takes nearly 4 times as much energy to produce 15 incandescent lamps as it does to produce one energy-saving lamp.

Using a 15 W energy-saving lamp instead of a 75 W incandescent lamp can save a total of nearly 1 megawatt hour of electricity during the operating life of the energy efficient lamp. Calculated in terms of CO2 emissions, this works out to roughly half a tonne less carbon dioxide. Moreover, if the extra energy required for the incandescent lamp is generated in a coal-fired power plant, then an extra 34 milligrams of mercury is released into the atmosphere - roughly ten times the amount that is contained in an energy-saving lamp. It is our job to develop energy efficient lamps and place them on the market. Afterwards it is up to consumers to decide if they prefer a lamp with a higher or lower degree of energy efficiency.

A comparison of three types of lamps

Energy required for the production and use in kilowatt hours (kWh)
Basis of the calculation: 15,000 hours of use