---
title: "Why is there a haze on the inside of your windshield?"
url: "https://maviautoglass.com/blog/why-is-there-a-haze-on-the-inside-of-your-windshield/"
description: "Why a hazy film builds up on the inside of a windshield, how to clean it without streaks and how to tell film from damage to the glass"
content_signal: ai-train=yes, search=yes, ai-input=yes
---

# Why is there a haze on the inside of your windshield?

Why a hazy film builds up on the inside of a windshield, how to clean it without streaks and how to tell film from damage to the glass

The haze on the inside of a windshield is usually a thin film that builds up on the glass, not a defect in the glass itself. A U.S. patent on removing this film describes it as consisting mostly of phthalate plasticizers vaporized from the polymeric materials used in vehicle interiors, which then condense on the glass. Smoke, vaping, fingerprints and cleaning product residue add to it. Automakers’ owner’s manuals, such as Kia’s and Mazda’s, say that when interior glass becomes covered with an oily, greasy or waxy film, it should be cleaned with a glass cleaner.

The film is easy to miss in daylight and obvious at night or in low sun, when it turns headlights and sunlight into glare. This guide is written by Mavi Auto Glass, a locally owned mobile auto glass company based in Roseville that replaces windshields across Sacramento, Roseville, Citrus Heights, Elk Grove and the rest of Greater Sacramento, where hot summers keep cabins warm for months. It explains where the film comes from, how to clean it without streaks and when haze is something else.

## Where does the film on the inside of the windshield come from?

Mostly from inside the car. The patent describes the windshield film as mostly phthalate plasticizers vaporized from various polymeric materials used in vehicle interiors ([US patent 4,313,841](https://patents.google.com/patent/US4313841)). Heat inside a parked car speeds up that release, and the vapor settles on the glass. Other sources build up on top of it.

- Smoke and vapor from smoking or vaping in the car
- Fingerprints and skin oils from touching the glass
- Residue from dashboard sprays and interior cleaners
- Dust from the vents settling on the glass

## How do you clean the inside of the windshield without streaks?

Use a glass cleaner, two clean cloths and a cool windshield. Here is the method in 5 steps.

- **Park in the shade:** let the glass cool so the cleaner does not dry before you wipe it.
- **Dust first:** wipe the glass with a dry microfiber cloth to remove loose dust.
- **Apply cleaner to the cloth:** spray the glass cleaner onto the cloth, not onto the glass, to keep it off the dashboard and the electronics behind the mirror.
- **Wipe in overlapping passes:** work from one side to the other, and reach the lower edge near the dashboard, where film is often heaviest.
- **Buff dry:** finish with a second clean, dry cloth.

Follow your owner’s manual for products. Some manuals warn that certain glass cleaners can damage the heating lines and antenna lines on rear and side glass, and if window film was added to your glass, check the film maker’s care instructions too.

## Is the haze always a film you can clean?

No. If the haze does not change after a careful cleaning, it may be something else. The table helps tell the common cases apart.

What you seeLikely causeWhat to doGreasy haze that smears when wipedFilm on the inside surfaceClean with glass cleaner and two clothsFog that clears with the defrosterMoisture condensing on the glassUse the defroster and fresh airTiny marks that glare at night and do not wipe offPitting or scratches on the outside surfaceHave the glass inspectedCloudy or discolored area inside the glassDamage between the glass layersHave the windshield inspected

Marks on the outside of the glass, such as scratches and pitting, are a different problem, covered in [whether windshield scratches can be polished out](https://maviautoglass.com/blog/can-windshield-scratches-be-polished-out/).

## How can you slow down the film from coming back?

Keep the cabin cooler and the glass cleaner. A sunshade and shaded parking reduce how hot the interior gets, which slows the release of vapors, and regular cleaning keeps the film from building up. Avoiding smoking and vaping in the car and wiping the dashboard with a cloth instead of spraying near the glass also help.

Be gentle around the mount behind the rearview mirror, where many vehicles have a driver assistance camera and sensors. If the windshield itself is damaged, a [windshield replacement](/service/windshield-replacement/) may be the fix, with [ADAS static and dynamic calibration](/service/adas-static-and-dynamic-calibration/) when the vehicle has a windshield camera.

## Before your next interior glass cleaning

Check your owner’s manual for the cleaning products it recommends, and keep two microfiber cloths in the car. Clean in the shade with the glass cool, start at the lower edge near the dashboard and buff dry. If the haze stays after a careful cleaning, look at the glass from outside at night and have it inspected if the marks do not wipe off.