Our guide to light bulb types and fittings

Light bulbs come in a range of types, with different fittings, and our guide is here to help you find the one you need.

LED Vs HalogenShop all light bulbs

Benefits of LED light bulbs

LED light bulbs will soon be the only type of bulb that you can buy in the UK. LED bulbs can last up to 25 years, far longer than halogen bulbs, which may need replacing after 1 year of use. LEDs are far more cost effective, saving you up to £240 a year, while halogens produce more heat and use 85% more power.

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Light bulb types and fittings

All light bulbs have a code to identify their type and fitting. The letters stand for the name of the fitting and the numbers are the diameter of the fitting in millimetres. There are usually LED and halogen options for both.


ES stands for Edison Screw and is one of the most common types of fitting. These light bulbs use a screw motion to slot into the fitting. The two types of ES are the E27 and the thinner E14 (sometimes called an SES).

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BC stands for bayonet cap. These bulbs use a twist and lock action to secure into the fitting, and the most common type is a B22.

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G4 and G9s, or capsule bulbs, are similar to bayonet caps, in that they need to be pushed in, twisted and locked. Most commonly used in cooker hoods.

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Also known as spotlight bulbs, they have two pins that connect into the spotlight socket.

Shop GU10/MR16 bulbs


This type of halogen bulb is commonly used in security lighting and floodlights.

Shop R7 bulbs

What our customers think

Wattage vs Lumens

Together, wattage and lumens define the brightness and energy efficiency of a light bulb. LED lights tend to give you more lumens, for far less wattage than halogen.


Wattage tells you how much power a bulb uses. More watts equal more power, but it doesn’t mean more brightness – for that you need to look at the lumens.


More lumens mean a brighter light. And for the greatest energy efficiency, you want to choose a bulb with the most lumens and least wattage.



These are the most commonly used shape of bulb.

Shop standard bulbs


Most likely to be found in kitchen lighting and appliances.

Shop capsule bulbs


Standard bulbs, with added style points.

Shop candle bulbs


Common in bathroom and kitchen lighting.

Shop spotlight bulbs


Used in floodlights and security lighting.

Shop linear bulbs

Warm or cold lighting?

Mood lighting

Some light bulbs have warm and cold tones, which is rated in kelvins. Candlelight is around 1,500 kelvins and 10,000 kelvins is equal to a blue sky. Standard bulbs have around 2,700 kelvins, but there are a range of options, letting you set the mood you want in your home.

More help and inspiration

Lighting buying guide

Your in-depth guide to lighting up your home.

Read our lighting buying guide

Kitchen lighting ideas

Bright ideas for choosing lights in your kitchen.

View kitchen lighting ideas

Bathroom lighting ideas

Let the light into your bathroom with inspirational ideas.

View bathroom lighting ideas

Smart lighting

Home lighting that you can control from your phone.

Shop smart lighting

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