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Energy saving light bulbs

Inefficient light bulbs continue to be phased out saving money and helping the environment

Traditional incandescent and the least efficient halogen light bulbs are being taken off the market in favour of energy efficient alternatives.

How do I choose the right light bulbs?

Follow our step-by-step guide to choosing an energy efficient light bulb.

1. Choose the right type of bulb

The table below indicates appropriate bulb types for different purposes: 

General lighting LED or CFL
Outdoor LED or CFL
Spotlighting LED spots
Dimmable lighting LED or B-rated halogen
Crystal chandelier LED

2. Choose the right lumen value

You may have bought a low energy light bulb at some point and been disappointed with its brightness or light colour.

Typically we are used to looking at Watts to determine how bright a bulb will be. Watts measures power consumption not brightness. Low energy bulbs use fewer Watts than traditional bulbs so you cannot look at Watts to gauge brightness of a low energy bulb.

Instead you have to look for a bulb’s lumen output. The table below shows the relationship between wattage of traditional bulbs and lumen values of LEDs/CFLs.

Traditional bulb LED / CFL bulb
15 watt 140 lumen
25 watt 250 lumen
40 watt 470 lumen
60 watt 800 lumen
75 watt 1,050 lumen
100 watt 1,520 lumen 

3. Choose the right colour

Most low energy light bulbs are designed to mimic traditional incandescent bulbs to some extent. Light bulbs that are described as ‘soft white’ or ‘warm white’ produce a light that is most similar to traditional bulbs and are best for general household lighting purposes.

Light bulbs that are described as ‘cool white’ or ‘pure white’ are good for use in the workplace or any area that requires clear vision.

Colour Rendering Index (CRI)

The Colour Rendering Index (CRI) of a bulb refers to how well a bulb will illuminate a given colour and is indicated on a bulb’s packaging. Two bulbs can have the same ‘soft white’ light colour but the bulb with a higher CRI will show colours more accurately than the others.

Traditional bulbs have a CRI of 100 but any energy saving bulb with a CRI of 80 or over will be appropriate for most household tasks.

Other useful information


We were the UK partner in the European funded PremiumLight project which aimed to increase the take-up of high quality, energy efficient lighting products. PremiumLight published results of laboratory testing of bulbs to help point you to the best products on the market. Since the conclusion of PremiumLight in November 2014, the follow-up project PremiumLight Pro aims to improve the energy efficiency of lighting tin the non-domestic sector.

Lighting Industry Association Verified

We partnered with the Lighting Industry Association (LIA) Laboratories to launch the LIA Verified scheme. This provides independent certification of the performance and safety of bulbs and luminaires to give you assurance about the quality of lighting products. 

More information

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