Light bulbs Light bulb FAQs

What's happened to traditional light bulbs?

Old-fashioned incandescent bulbs have been phased out across Europe. Most mainstream shops have already phased out all incandescent bulbs and this means the last old fashioned bulbs in corner shops and specialists will soon also be gone.

Find out which light bulbs are worth your money with our Best Buy light bulbs reviews. 

What are the different types of light bulbs I can buy?

There are three types of energy-saving light bulb:

• Compact fluorescent lamps (CFLs)
• Halogens 
• Light-emitting diodes (LEDs)

Visit our page on how to buy light bulbs for more details.

Will using energy-saving light bulbs save me money?

In most homes, lighting accounts for about 15% of the electricity bill and, although efficient light bulbs can cost more to buy, they are much cheaper to run. Each CFL bulb (the most common style of energy-saving light bulb) can reduce your electricity bill by around £3 a year, so replacing all your light bulbs with energy-saving ones could save you £55 a year, according to the Energy Saving Trust.

Why are CFL light bulbs more expensive than they used to be?

Until 2010, energy companies subsidised and even gave away CFL light bulbs to UK homes. But following concerns that consumers were not using the bulbs given to them, these direct promotions were banned and that has meant that the price of CFL bulbs has increased in the past few years. 

Which wattage of light bulb should I replace my traditional light bulb with?

Read our how to buy light bulbs guide to find out what  wattage and lumens translate into for each type of light bulb.

Do energy-saving bulbs struggle to get bright when you first switch them on?

This is only a problem with CFLs, as LEDs and halogens come on instantly. At Which?, we check the light output of the bulbs we rate when they are first turned on and then at intervals to ensure measured light output meets what’s promised on the packaging. The results of our independent testing show which bulbs give out a good level of light at start-up and those that don't. Go to our light bulb reviews section to find the best and worst.

Can I use energy-saving bulbs in cold rooms or outside?

Colder temperatures are only a problem for CFLs, as LEDs and halogens should work well at all temperatures. We test the performance of CFLs at both 5ºC and -10ºC, and have found that CFLs often don't work well at low temperatures so would not be suitable for lighting colder areas of your home, such as a garage. 

Can I use energy-saving bulbs with dimmers?

A bulb's suitability for use with dimmers should be written on the packaging, so check the box before you buy. 

However, some dimmer switches may not be compatible with newer types of bulbs. In general: 

• CFLs and halogen bulbs - most modern dimmer switches should work with these bulbs although some older ones may not be compatible.
• LEDs - you may need to upgrade your dimmer switch to cope with low electrical loads. If in doubt, ask an electrician to check. 

Can I find bulbs for chandelier-style light fittings?

Manufacturers now produce light bulbs in many more shapes and sizes than they used to - for example candle and smaller globe-shaped bulbs.

Since I started using LED lights, my digital radio is playing up. Can LED bulbs affect digital radios?

Yes, we have found that some cheaper LED bulbs do affect radios. If you notice fuzzy reception it could be due to it being too close to a light bulb. In a snapshot test we sent some cheap generic LED bulbs to our test lab and found that a digital radio’s signal went fuzzy when placed within a few metres of the switched-on bulbs. The radio completely cut out when it was within a few centimetres.

We also conducted tests on a more expensive branded 240V GU10 LED and some halogens, and found no interference.

Which? was first alerted to this problem when a member told us his radio had stopped working after replacing all his kitchen lights with generic LED bulbs. LEDs are ultra-efficient light bulbs that can last up to 20 years and have been hailed as the future of home lighting. We need your help to find out more: if you have had interference, let us know the bulb type and brand. We also want to hear from
you if you know why this is happening. Find out how to contact us here.

How can I dispose of used energy-saving light bulbs? 

LEDs and halogens can be disposed of in your normal household waste. CFLs contain very small amounts of mercury and need to be recycled rather than going in the bin. 

You can find your nearest local recycling site by entering your postcode on the Recolight website. Homebase, Ikea, Robert Dyas and larger branches of Sainsbury's also often have recycling points in store.

You can also use our interactive recycling tool to show you how you can dispose of unwanted electrical goods.

More on this...

• Find out about the different types of energy saving light bulbs
• See how we test energy saving light bulbs