Please address your answers and questions to ' Curiosities '. In the mid-1970s I asked the same question of the then Scottish Electricity Board. They sent out a man to explain to me the mysteries of starting and running . MM Hendry, Edinburgh, Scotland.
Fluorescent lights consume less energy than incandescent bulbs to give the same amount of light.
But fluorescent light bulbs contain a device called a ballast to start the lamp and regulate the electric current. The ballast consumes extra power when the lamp is switched on so the running costs of a fluorescent light will not be lower if the lamp is regularly switched on and off. However, of greater economic concern is the effect on life expectancy of the bulb. The UK Consumers Association has run tests on fluorescent lights and notes that regularly switching a lamp on for only five minutes could result in it lasting just 20 per cent of its rated life. And fluorescent lights are expensive to replace.