Stopping condensation in your headlights

Condensation inside your headlights can make driving at night dangerous, reducing both your view of the road and your visibility to others. It’s a common problem, especially in humid or colder weather.

But what causes headlamp condensation? And how can you prevent it from happening? We’ve compiled this guide to explain the causes of condensation, and how Halfords can help you to solve it.

Why do car headlights fog up?

The cause of condensation in headlights is the same as any other form of condensation – glass and windows mist up when the air outside is a lower temperature than the air on the inside, which is why condensation is more common in colder months.

Your headlights will fog up if there’s damage to the lens, casing, or seals, as this will let in moisture. The seals on your headlights are designed to keep the area water-tight, so if there are any splits or cracks, then moisture will work its way into your headlight and increase the risk of condensation.

If this kind of damage is causing your headlights to fog up, then the issue could be exacerbated if you have LED or Xenon bulbs. This is because traditional halogen bulbs emit more heat than these newer varieties, and it’s this heat that clears away condensation quickly. So, since newer bulbs don’t emit much heat, it takes longer for the condensation to clear.

How can I stop condensation in headlights?

To counteract any unwanted fogging, you’ll first need to find the cause of the problem:

Blocked vents

Some headlamp units will have venting to allow changes in air pressure, but over time these can become blocked with debris and dirt from the road. If these vents are blocked, then moisture can become trapped inside the headlight, leading to condensation. So, we’d advise you check that your vents haven’t become congested.

The exact location of these vents will vary depending on the make and model of your vehicle, but you should be able to find this information in your owner’s manual. If you do need to clear away any debris, you can do this by wiping the vent or blowing with compressed air. Just be careful not to push it into the headlight housing, as you’ll need to break the seal to remove it.

Damaged seal

Your headlamp seal joins the lens to the back casing and ensures that the entire headlight assembly is both air and watertight. If this seal is damaged or incorrectly fitted, then moisture will be able to enter the headlamp unit and create condensation.

Stone chip holes or cracks in the lens

Over their lifetime, your headlights are likely to accumulate some wear; any small stones or other debris flicked up from the surface of the road as you’re driving can lead to holes and cracks in the casing and lens. These holes and cracks allow in moisture, which in turn can lead to condensation.

If this is the case, and there’s significant damage to the lens, then you may need to replace the entire headlamp unit. If so, you can find the part you need at with our easy registration tool. Just enter your vehicle registration number and we’ll show you all the available parts that fit your vehicle.

Once the unit has been replaced, we also advise that you have your headlamps realigned – incorrectly aligned headlamps can dazzle other road users, and may reduce your view of the road ahead. You can book an alignment at your local garage online at

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