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Single Beam Vs Dual Beam: What’s The Difference

March 6, 2024
Single Beam Vs Dual Beam

Table of contents

This is the basic difference between single beam and dual beam headlights and their names make it easy to get the two confused.

This article explains the difference between single beam and dual beam headlights, the pros and cons of both systems, and how you can choose the right type of headlight for your car. Join us as we demystify this topic today.

What are Single Beam Headlights?

Single beam headlights have one set of bulbs for the low beams and another set of bulbs for the high beams. This means the headlight system in the car has 2 bulbs on either side.

The name single beam refers to the fact that each bulb only produces one type of beam, either a high beam or a low beam. To achieve this, each headlight housing has two reflectors, one for the low beam bulb and another for the high beam bulb.

Advantages of Single Beam Headlights

Some of the pros of single beam headlights are:

  • According to some lighting experts, the quality of illumination from single beam headlights is better. This is because each single beam headlight bulb is made with only one purpose, to produce a high beam or a low beam.
  • The cost of replacing one of these single beam bulbs can also be lower than replacing a dual beam bulb. Dual beam bulbs are more complex to manufacture and this is more expensive to produce each. However, if you have to replace all the single beam headlight bulbs at the same time, this may eliminate the cost savings.
  • There is less chance of losing all the lighting from one side of your car. If one of your high beam bulbs suddenly fails you could still safely use your low beams to get home. 

Disadvantages of Single Beam Headlights

Some of the drawbacks of a single beam headlight system are:

  • Upgrading your headlights means having to buy twice the amount of bulbs and this can get expensive. 

What Are Dual Beam Headlights?

A dual beam headlight uses a single bulb that handles both the low and high beams. This means the headlight system in the car will only have 2 bulbs, one for the headlight on either side.

Red car with a dual beam headlight

The name dual beam refers to the bulb’s ability to produce two different types of light beams depending on the setting. The headlight housing only has one reflector and can only accommodate one bulb. 

Advantages of Dual Beam Headlights

Some of the pros of dual beam headlights are:

  • When upgrading your headlights, you only need to buy a single pair of dual beam headlight bulbs and this can be less expensive compared to buying two pairs for the single beam systems.
  • Replacing two bulbs takes less time than replacing four.

Disadvantages of Dual Beam Headlights

Some key drawbacks of dual beam headlights are:

  • A pair of dual beam headlight bulbs cost more than a pair of single beam headlight bulbs. This is because each dual beam headlight bulb is more complicated to manufacture.
  • The quality of light from a dual beam bulb may not be as good as the quality of light from a single beam bulb since each bulb must serve two functions.

Single Beam Vs Dual Beam Headlight Systems

The table below highlights the similarities and differences in different features of single beam and dual beam headlight systems.

Feature Single Beam Headlights Dual Beam Headlights
No. of Bulbs in each Headlight Housing 2 1
No. of beam settings per bulb 1 2
Price Per Bulb Lower Higher
Halogen Option Available Available
HID Option Available Available
Led Option Available Available

Single Beam and Dual Beam Headlights in Halogen, HID, and LED Headlights

You can get single beam and dual beam headlight bulbs for halogen, HID, and LED bulbs. The operation of the single beam bulbs is straightforward but the dual beam bulbs work in unique ways.

Halogen Single Beam Vs Dual Beam

A single beam halogen headlight bulb has one filament while a dual beam bulb has two filaments. In the dual beam bulb, one filament is for the low beam and the other is for the high beam.

The two filaments are set at different heights. This is because the distance of the light source from the reflector affects the beam pattern.

LED Single Beam Vs Dual Beam

A single beam LED headlight bulb will have a set of light-emitting diodes that all turn on and off at the same time. The dual beam LED headlight bulb will have two sets of LEDs that turn on and off interchangeably depending on the headlight setting. 

Just as with halogen bulbs, you may notice that the different sets of LEDs in dual beam bulbs are slightly offset from each other. This ensures the beam patterns remain close to what you’d get with dual beam halogen bulbs for low and high beams.

HID Single Beam Vs Dual Beam

Unlike halogen and LED bulbs, HID bulbs don’t have a solid part that produces light. The light comes from a heated gas plasma in the bulb. Unfortunately, having two separate HID systems in the same bulb isn’t realistic.

As a result, the dual beam headlight system for HID bulbs works by changing the position of the glass bulb inside the housing. 

When activated, an electromagnet pulls the glass bulb closer to the reflector and this changes the beam pattern just like the distance offset between the two filaments in a dual beam halogen bulb. 

Choosing the Right Headlight Beam System

When buying a car, you may have the option of getting dual beam headlights or single beam headlights. Either option should be adequate, but one may be a slightly better choice for you. Here are a few things to consider when making this decision.

Headlight Beam

1. Quality of Illumination

Single beam headlights may offer a better quality of illumination. Each bulb is made for a single purpose and each reflector is designed to produce one beam pattern. This can result in better illumination in both high and low beam settings.

2. Cost

Understanding the true cost of single and dual beam headlights is a challenge. For single beam headlights, you should consider the cost of swapping all four bulbs vs the cost of only swapping two bulbs in a dual beam headlight system.

However, headlight bulbs are usually swapped in pairs so you may not need to change your high beam and low beam bulbs at the same time in a single beam headlight system.

The upfront costs of both setups will depend on the car manufacturer, vehicle model, and other factors. Thus, you have to review these on a case-by-case basis.

3. Convenience

Watch showing time.

If you ever need to swap all your headlight bulbs, changing two bulbs is much faster than changing four. This is where dual beam headlights have the advantage.

4. Safety

When using a dual beam setup, there is a greater risk of having no lights at all on one side of your vehicle. Dual beam headlights only have one bulb on each side. In case this bulb fails or if there is a fault in the wiring, you could easily lose both the low and high beam functions.

Single beam headlights have two bulbs on either side. If one bulb suddenly fails on the road, you could switch to the other headlight setting and still have functioning lights on both sides of your car. This could be important for frequent night drivers.

5. Aesthetics

Red car with a sleek single beam headlight

Depending on the model of your car, you may prefer the aesthetics of either single beam or dual beam headlights. Aesthetics are subjective so only you know what looks good to you.

Can You Use a Dual Beam Bulb in a Single Beam Headlight Housing?

Dual beam bulbs are not designed to work in single beam headlight housings and vice versa. Installing the incorrect bulb type in the headlight could damage the bulb. At the very least, it simply won’t turn on because of differences in the electrical systems that power them.

Additionally, even using the wrong dual beam bulb in a dual beam headlight housing may damage the bulb. Headlight bulbs have additional differences such as their sizes and wattage. Consult your owner’s manual to get a list of compatible bulb types before making a purchase.


The terms single beam and dual beam can be confusing for those who don’t know much about automotive lights. Luckily, these two types of headlights are easy to tell apart thanks to differences in the bulbs and headlight housings.

Neither headlight type has a significant edge over the other and users may simply have to choose the one that looks better on their car. However, care should be taken to only use compatible bulbs in either type of headlight.

Why You Should Trust Carlightvision for Your Single Beam and Dual Beam Bulbs

Carlightvision‘s dual beam and single beam headlight bulbs have been lighting up roads all over the world for more than 15 years. More than 100 brands trust our LED bulbs and our R&D department produces hundreds of new designs each year. Check out some of our LED bulbs on our product page and be sure to ask about our OEM and ODM services.


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Hey there, I'm Mark Yang, Hope my blog posts can help you. I have been in the car light field for more than 20 years. So if you have any questions, I'm always happy to help you.
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