Firstly, how do we measure the whiteness of a bulb? Bulb manufacturers indicate the whiteness of their bulbs with a measurement known as colour temperature. This tells you whether the light produced is warm or cool. This is expressed in units called Kelvins (K).
A lower colour temperature means that the bulb has a more yellow tone. Bulbs with a colour temperature of 3000K are extremely yellow. These might be used as fog lights.
A higher colour temperature indicates a bulb with a blue tone. Xenon HID bulbs with colour temperatures as high as 8000K will have a noticable blue tint. Bulbs with a colour temperature over 8000K are very blue and give off significantly less light.
The whitest bulbs are those that measure around 5000K. This is a great balance between yellow and blue - bulbs at this colour temperature produce a light that is bright and clear. Some drivers prefer bulbs at 6000K, but these have a hint of blue that makes them slightly less bright than a bulb with a colour temperature of 5000K.
One of the reasons HID bulbs have become so popular is that they give off extremely bright, white light. But, some HID bulbs are whiter than others. There's several ranges of HID headlight bulbs that offer a very white light. First up is the OSRAM Xenarc Night Breaker Laser Next Gen range. These are high performance lighintg with up to 220% more brightness from the D3S and D4S fitments, and up to 200% from the D1S and D2S fitments. They boast a kelvin rating of 4500K and a lifetime expectancy of 1,500 hours. This innovative HID technology is the newst from OSRAM giving you 20% whiter ligght and increased brightness without the risk of glare - the perfect upgrade!
However, there is an even whiter option - Philips Xenon WhiteVision gen2. This range produces a colour temperature of 4800K, giving you a bright, white light for a super stylish look on the road.
If you're after a very strong effect, choose OSRAM Xenarc Cool Blue Intense. With a colour temperature of up to 6000K, these bulbs achieve an ice white light with a slight blue tint for a strong, modern look.
Shop styling xenon HIDs here.
Although xenon HIDs are the best option for those seeking the whitest headlight bulbs, there are plenty of white H7 bulbs options too.
If you want halogen headlight bulbs that are a close colour match to factory-fitted xenon HIDs, you should choose Philips Diamond Vision. This range has a colour temperature of up to 5000K, giving you a bright, white light that will look similar to a HID. However, it's worth noting that Philips Diamond Vision, along with many styling bulbs, are not road legal.
If you want a road legal halogen that produces a white light, we would recommend white H7 bulbs or the OSRAM Cool Blue Intense. Even though the colour temperature of the range is up to 4200K, you'll still get a whiter light than standard on the road.
There are different headlight colours available on the market, not just your usual white. So, what colours are available and which are legal? Find out more here.
Shop Styling Halogen Headlight Bulbs here.
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About the Author
John Conboy is the founder of PowerBulbs.com, a UK based automotive lighting specialist, which ships bulbs worldwide. John has 20+ years experience in the industry and in that time has become an approved partner of Philips and OSRAM.