The Difference Between Halogen, HID, and LED Light Bulbs

You may or may not be surprised, but picking a type of light bulb for an upgrade or replacement is surprisingly tough. Not to mention all of the conflicting information online about each kind. There are three prevailing types of automotive lighting: halogen, LED, and HID. So let's dive into what they are, how they work, and which may be best for your given application.

Let there be light!

Whether or not you can actually upgrade your lights depends on the type of headlights your car is equipped with. A lot of newer cars already come equipped with LED headlights that are sealed and would require an entire aftermarket headlight assembly. That gets expensive and those stock headlights are usually pretty good from the factory. Even modern cars that come with HIDs are somewhat limited, but can still be upgraded fairly easily. 

There are also two main types of headlights: reflector and projector. Reflectors are the most common and look like chrome mirrors inside the headlight housing. Projectors are less common and look like a glass globe that works literally like a projector, and is the most effective headlight style. Both types can accept all bulbs, but must be designed for their specific type of bulb.

Folks with halogen headlights are in luck because they have the most choices. Most of the headlight bulb aftermarket is centered around upgrading halogen lights into something brighter, more modern, and longer lasting. Let’s go over the three prevailing types of lights and their advantages and disadvantages.

Halogen bulbs are the oldest and most prevalent lighting technology of the three. Invented in the 1800s, the operating principles of halogen lamps are simple as it works like an incandescent bulb that you would see in a home application. But this bulb uses a different, more powerful filament to increase brightness substantially. 

The filament is the thin wire in the middle of the bulb that uses electrical current to generate light. On its own, it wouldn’t be bright, so the filament is enclosed in a glass bulb filled with an inert gas mixed with a halogen element like iodine. Combined with a filament made of tungsten, a chemical reaction allows the filament to burn super bright, making it ideal for headlights. 

It’s an incredibly simple technology that is cheap and easy to replace, but halogen bulbs wear out regularly. As the filament expands and contracts from heat, it can break and cause the light to fail completely. Most halogen lights have a life of around 2,000 hours, which is a fraction of the life of LEDs and HIDs. Also, the technology is inefficient and uses a lot of energy. European countries are phasing out the sale of halogen bulbs in favor of LEDs, meaning it might get harder to find replacements in the long term.

In terms of light output, halogens are very strong. Most of the work is done by a well-designed headlight reflector or projector, but halogens are up to the task of lighting the road and are arguably brighter than some aftermarket LEDs. Overall, they’re a better choice than most people give them credit for, especially for a quality set of halogens. 

HID means high-intensity discharge. It’s a technology that’s almost as old as halogen but has seen less widespread use due to cost and complexity. There are similarities between HIDs and halogens but they fundamentally operate in different ways. Instead of a filament, the light is generated from an arc of electricity across a gap of two tungsten electrodes. It’s all housed within a bulb of noble gas and metals to influence color temperature and brightness.

It’s a bit more complicated to run an HID bulb. Instead of just a standalone bulb like the halogen and LED, HIDs require a ballast and sometimes an ignitor to run the bulb. HIDs are also the most expensive to buy, costing hundreds of dollars for the full ballast and bulb setup. Because of their similarity in terms of light pattern to a halogen, they can be run in a halogen reflector but with heavy caveats. Only some halogen reflectors are designed to run an HID, and you run the risk of serious glare. Do research on your application before installing it.

It’s the brightest of the three types of bulbs by far, with extreme light output and excellent versatility. The aftermarket behind HIDs is also the largest, with entire businesses dedicated to selling aftermarket HID lighting. One of my personal favorites is The Retrofit Source. If you’re after raw brightness, HIDs are the only way, but they are expensive and more complicated to run. They also last long, offering a generally accepted 10,000-hour lifespan.

LEDs are the newest technology and the simplest one. With just a diode that directly emits light, LEDs are cheap, ultra-efficient, lightweight, and incredibly simple to run. 

The downsides to LEDs are primarily an issue of light output. LEDs can be extremely bright, but the size of the light source is a fraction of the halogen and HIDs, making focusing the light much more difficult. The properties of LED light also don’t lend themselves to long-distance light output but plenty of extremely bright flood light. This makes an LED light upgrade for a halogen car a more complicated proposition than most people think. 

There are LED bulbs designed to work in halogen housings but the results vary greatly. But the technology is still developing and could become a more serious contender. Rather than headlight bulb swaps, LEDs have a great home in fog lights, turn signals, and brake lights. They're also heavily used in the off-road community with light bars, spotlights, and more. The Drive's Jonathon Klein recently installed a set of off-road LED lights on his Can-Am Maverick project.

They also have an attractive instant-on and instant-off effect that modernizes old cars.

A host of new cars today now come with LED headlights, which means they will become more common and less expensive. With an exceptional lifespan of around 50,000 hours, LEDs are something of a no-brainer but might not work exactly as intended.

At the end of the day, upgrading lighting comes with a lot more caveats than we like to discuss. Sure, headlights can be a lot brighter than factory, but there is always the risk of glare that can blind other drivers on the road. 

Keeping social consciousness in mind, upgrading from a halogen requires more work than a drop-in bulb. Retrofitting a projector, something I’ll do a step-by-step guide on in the future, is a way that makes upgrading to an LED or HID safe and legal, depending on the jurisdiction. Likewise, some LED lights are banned from on-road use, i.e. most off-road accessory lights.

But what you should buy depends on your car and your budget. If it were up to me, I’d always upgrade a halogen car with a high-quality halogen bulb before spending money on a plug-and-play LED or HID bulb. Yes, the other kinds of bulbs are better but they are a nuisance to other drivers without the right supporting mods. 

But now you’re armed with the right information to make a choice. Don’t let those old burnt-out headlights stay dim for long.

The Drive and its partners may earn a commission if you purchase a product through one of our links. Read more.