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Energy-saving light bulb FAQs

The following are some of the frequently asked questions (FAQs) about energy-saving light bulbs. For more detailed information, we recommend that you start with our Introduction to energy-saving light bulbs, and follow the pages in this guide in the order listed there.

Don't energy-saving light bulbs flicker?

No, they don't. Some of the old ones might do if they're broken. If you've got a bulb that flickers, replace it.

Does it use more electricity to turn the light off and on again than to leave it on?

CFL bulbs need a short burst of extra energy when they come on, no more than a few seconds of normal operation. It can shorten the life of the bulb if you turn it on and off a lot, however. Turn the light off if you’re leaving the room for 15 minutes or more. Do leave energy saving bulbs on in places where you need the light to keep you safe (on the stairs etc), so you don’t have to wait for them to warm up.

Can I use a 75-watt equivalent CFL bulb in a lamp shade that can only take bulbs up to 40 watts?

Yes, you can. It's the actual wattage that matters here (and most CFL bulbs use much less than 40 watts). The 'watts equivalent' figure is a measure of the power consumption of the bulb, not a measure of light brightness. Lumens (lm) is the measure of light output and this is the number to use when choosing a bulb.

Can I use energy-saving light bulbs in cold areas?

CFLs take longer to start up when they are cold. If you need light quickly in colder areas outside or in a garage or pantry, for example, a halogen or LED bulb is better.

How do I dispose of energy-saving light bulbs?

All bulbs should be recycled rather than disposed of in the general waste. CFL bulbs in particular need to be treated carefully as they contain mercury, which could be dangerous. If your council provides collection points for CFL bulbs, use these.

Alternatively, your electrical shop should accept a used bulb from you. Most will do this quite happily as long as you are buying a replacement bulb from them. It's a good idea to take the old bulb along to the shop anyway, so that they can help you find something similar (or different).

Last updated: June 2014

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