1) Identify the bulb type (H1, H4, H7, etc.)

Each vehicle uses one or more specific bulb references. If you choose the wrong one, the bulb will not fit the optic. To avoid mistakes, check:

• The manufacturer's manual: It mentions the exact reference (e.g.: H7 12V 55W).
• The back of the headlight: Often, an inscription indicates the standard (H1, H4, H7, etc.).
• Specialized websites: You can enter your car model to get the reference.

Example: a Clio 4 often uses H7 for low beams, while a 206 is equipped with H4.

2) Halogen, LED, or Xenon: What's the difference?

Once you've found the reference (H1/H4/H7), you need to choose the technology:

• Halogen: The most common. Yellowish light (~3200K), very low price, easy installation. Ideal if you want something "cheap" and compliant. The H4 bulb is one of the most well-known.
• LED: Intense white light (~6000K), reduced consumption, lifespan up to 5 times longer than halogen. An LED bulb for cars is perfect for those who drive a lot at night.
• Xenon: Reserved for vehicles equipped at the factory. Powerful lighting, but complex installation.

3) Performance: What to look for?

Not all bulbs are equal. Here are the criteria to check:

• Luminous power: Some halogens show +30% to +150% more light vs standard.
• Lifespan: A standard bulb lasts 400-600 hours, an LED can exceed 20,000 hours.
• Color: 3200K (warm yellow), 4300K (natural white), 6000K (cool white "xenon effect").

Tip: Choose a "more light" bulb if you drive at night outside urban areas.

4) Homologation and legality

In France and Europe, only certain LED references are approved to replace halogens. If the bulb is not approved, it can lead to a refusal at the technical inspection or a fine. To be safe, always choose a bulb compliant with ECE R37 (halogen) or ECE R128 (LED).

FAQ

• What is the difference between an H4 and an H7?
  The H4 combines low beam + high beam (double filament). The H7 is a single filament (a single use, often low beam). The two are not interchangeable. See this article for more details.
• Can I switch from a halogen to an LED?
  Yes, but only if your LED bulb is approved and compatible with your vehicle.
• Should I change both bulbs at the same time?
  It is advisable for a uniform result and to avoid a second one failing quickly.