Lifespan of energy-saving bulbs reduced by repeated switching

The lifespan of energy-saving light bulbs can be reduced by up to 85 per cent if they are switched off and on too often, it has emerged, as traditional bulbs are phased out to cut carbon dioxide emissions.

Published: 4:30PM BST 01 Sep 2009
Manufacturers of energy-saving fluorescent bulbs state that they last between 6,000 and 15,000 hours.
Those sold in Britain last on average 10 times longer than old-style incandescent light bulbs, which had an official lifespan of about 1,000 hours.

The longer life-expectancy of the bulbs – which use up to 80 per cent less electricity – has been held as a justification for their higher price, which is set at £5 each by some retailers.
From September 1, incandescent bulbs were outlawed from being imported to EU countries in order to save energy and cut emissions.
Yet repeated off-on switching of the energy-saving versions can significantly reduce a fluorescent bulb’s lifespan, according to the Energy Saving Trust (EST).
It says: “Turning the bulb on and off repeatedly may shorten its life.”
It advises that “to help it last as long as possible, it is best to leave it on for a 'stabilising' period of 10 to 15 minutes at a time.”
However, it states: “Normal household use shouldn't cause any problems.”
A spokesman for the EST said: “Regularly flicking a bulb on for a brief moment and then off again is not recommended as it can shorten the lifetime of the bulb.
“The reason is that the electronics in a CFL’s ballast need time to charge up and interrupting this process can reduce the lifetime of these components.
“However this would be quite an unusual way to operate your lights.”
The spokesman added that all bulbs approved by the EST must maintain their lifespan during tests involving “thousands of on/off cycles”.
Critics have suggested that home owners could exploit the loose language of the new regulation, which refers only to "household lamps".
Complaints have also been made about the poorer quality of light produced by the energy-saving bulbs and the fact that they contain mercury, which is poisonous.
Some home light fittings must be replaced to carry the new bulbs while the vast majority of fluorescent bulbs cannot be used with a dimmer switch.