Should you be worried about LED lighting quality?We reveal what you need to know about LED lights

02 June 2015

LED and Incandescent Lightbulbs 2

LED light bulbs can now look just like the old bulbs, but is the light the same?

Which? tests have discovered that the quality of light you get from LED light bulbs can't quite match old-style bulbs and halogen light bulbs. Read on to find out how this affects the lighting in your home.

LED lighting has made big strides in the relatively short period that has been used for domestic lighting. However, our testing has revealed that LED light bulbs still have a little way to go to match the very best standards of old incandescant light bulbs and halogen bulbs when it comes to light quality.

Light quality boils down to two things - light colour and light rendering. Imagine buying a bulb that emits a lovely orange glow (light colour) and then finding that it gives the red trousers you slipped on that morning a distinctly orange hue (light rendering).  

Poor quality bulbs score poorly in our light rendering tests.

To see which light bulbs aced our rigorous tests, including LED bulbs for only £5, go straight to our .

LED light bulbs and light rendering 

CRI chopping board

A chopping board shot under light with a CRI value of 100

Light rendering is where a lot of people fall foul when they are buying new light bulbs. You could get the light colour of your dreams, only to get it home and discover that it has strange impacts on the colour and appearance of certain items in your home. 

Rendering is measured on the Colour Rendering Index (CRI) and is the ability of a light source to truthfully represent a colour. The higher the CRI score out of 100, the more accurate the light source. 

Put simply, you want a bulb with a high score so you can guarantee that your tomatoes will look red on your chopping board and not an odd yellowy colour. 

Use the two images to the right to decide whether you can live with a light source with poorer rendering. 

CRI chopping board 2

A chopping board shot under light with a CRI value of 80

Our testing has revealed that LED and CFL lighting can comfortably achieve CRI scores in the mid 80s, which is considered an acceptable level. 

The best LED light bulb we tested has a CRI score of 91. To find out which bulb this is, head straight to our .

A score of 91 is still some way off the very near perfect colour rendering of a halogen or old incandescent bulb, which get 99 or 100 on the CRI scale. 

You will need to decide for yourself whether the large energy savings that LED light bulbs provide are worth the small reduction in the quality of their light rendering.

LED light colour

Light colour is also very important. You wouldn't want your lounge or hallways bathed with a stark white or bluey light that's more familiar with a hospital waiting room than a comfortable living space. This is why you should pay close attention to the colour temperature score given to each light bulb on its packaging.

The colour of light is measured on the Kelvin scale, which is actually a measure of temperature. This is why light bulb manufacturers refer to the colour of the light as the 'colour temperature' on the bulbs' packaging.


Most people have become used to the warm yellow light given out by the old style incandescent bulbs, which is 2,700 on the Kelvin scale. Use the chart, above, to see where your light colour preference lies on the Kelvin scale and keep it in mind the next time you are choosing a bulb. 

Manufacturers have got pretty good at getting a wide variety of colour temperatures from any type of energy-saving light bulb, so you should be able to find a colour you like regardless of whether you want to buy an LED, CFL (Compact Fluorescent Light) or a halogen bulb.

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