There's a lot of confusion about the legality of xenon bulbs. This confusion is derived from a number of factors which we'll discuss here.
The term 'xenon'
Xenon is a gas, just like halogen. Xenon gas can be used in two applications in automotive lighting.
1. Xenon HID gas discharge systems - lamps such as D2S, D2R etc.
This is a modern and powerful headlight system and very different from the halogen based headlights that are in most cars. For it to be road legal it has to be factory fitted with the car - this is for safety reasons.
There are ways to add it as an aftermarket addition. Most of these are in the form of illegal HID kits. We sell replacement xenon HID bulbs for cars with xenon HID that has been factory fitted. The factory fitted version is perfectly road legal and the lamps tend to need to be replaced every 4-5 years.
2. Halogen bulbs with a xenon gas mix - products such as Philips X-treme Vision
Most vehicles continue to use a halogen headlight unit which uses a halogen bulb. The advantage is that it is cost effective and simple to change the bulbs, but the downside is that standard halogen bulbs do not deliver significant amount of light.
However, thanks to advances in technology over the last decade, motorists can now upgrade their halogen bulbs by replacing them with products that use a xenon/halogen gas mix. The refined design of the bulb, and the use of the more efficient xenon gas, means that increases of up to 100% can be delivered with no increase in wattage. One leading example is Philips Extreme Vision.
These upgrade lamps can be fully road legal if sourced from a quality and reputable supplier such as Philips or OSRAM. It's important to ensure you purchase the correct fitting of bulb for your vehicle - if you're not sure of this then you can check this in your vehicle handbook or with our online vehicle database.
What about high wattage lamps?
We do not generally recommend customers use high wattage lamps for several reasons. Firstly, they're not road legal. Secondly, they generate significant amounts of heat which can melt or discolour plastic lenses, so relays and other modifications need to be implemented. Thirdly, the longevity tends to be very poor so bulbs will need to be changed more frequently. With new advances in upgrade halogen/xenon bulbs, it's no longer necessary to use high wattage lamps in normal driving conditions.