Do Car Windshield Water Repellent Coatings Work? Should You Use It?

Ollie Barker

Do Car Windshield Water Repellent Coatings Work

Do Car Windshield Water Repellent Coatings Work
Drivers are often confused with the difficulty of seeing in bad weather. There are various solutions to improve wet weather driving visibility, but many people aren’t sure do car windshield water repellent coatings work? In this article, I will go into deep detail about windshield water repellent coatings.

What Is Windshield Water Repellent Coating?

Water repellent coatings are thin transparent films that are applied on the surface of your windshield. The purpose of applying this coating is to inhibit water from adhering to the glass surface. As a result, fewer water droplets remain on your windshield even in the pouring rain.

Many brands have released windshield water repellent coatings to help drivers see better in rainy weather.
The water repellent will also help you maintain a shiny, clean windshield at all times. It can be used in all weather conditions as well.

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How Water Repellents Work? & Do Car Windshield Water Repellent Coatings Work?

The water repellent works by creating a hydrophobic barrier on the glass. Since water droplets are not able to make proper contact with the glass, they slide off. It’s important to note that this technology doesn’t repel every single water drop or eliminate the rain; it just keeps your windshield clear and clean. But I’m pretty sure that what drivers need.

With high-quality water repellent coatings, drivers will have better vision during heavy rain or snow.

Water repellent applied just like paint to the surface of the glass, and it creates a hydrophobic barrier between the glass and water drops. The result is that water will bead up on the windshield rather than stick to it. It is generally recommended to apply it during overcast days or indoors.

Driving in heavy rain and snow can be quite challenging for many drivers. Wiper blades aren’t always enough to keep a clear view of the road when visibility is limited by heavy precipitation.

Differences in PDMS vs FAS

There are two types of commercially availably windshield water repellents: polymer-dispersed liquid crystal and fluorochemical acrylic.

Polymer-Dispersed Liquid Crystal (PDMS) Windshield Water Repellents

This type of windshield water repellent is most commonly used by manufacturers. They are applied onto the glass of your windshields using a water-based, silicone-based or urethane dispersion process. The PDMS windshield water repellent can have a thickness of 10 microns as well as 2 and 5 microns thick.

The polymer-dispersed liquid crystal is able to reduce optical distortion and visibility problems by more than 70% (about 30%) as compared with other traditional silicone-based materials.


FAS is short for fluorochemical acrylic. This type of windshield water repellent is applied onto the glass using a dispersion of liquid chromic acid. The FAS is a thin coating that can be applied in air or an inert medium such as polyvinyl alcohol (PVA). Typically, it’s thicker than PDMS and has an average thickness of 9 microns.

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Both windshield water repellents work great but they are different in many ways.

Where Can You Use It?

So, is windshield water repellent coating used for windshield only? The answer is NO. You can actually use this product to protect all your vehicle’s glasses from not just wettability but also cracks, stones, and chips as well.

However, one thing I never do is to apply water repellent coating to interior glasses as the chemical smell is very harmful and it may damage the tinted glass.

Advantages Of Using Water Repellent Coatings

Let me ask the question again: do car windshield repellent coatings work? Beside giving the windshield a clearer vision during the rain and snow, the water repellent coating can bring you various benefits.

1. Water Repellent Coatings Protect Glass From Damage

In the harsh condition of rain and snow, most windshields can be damaged over time. The windshields will have rust spots, scratches, chips, and cracks. This is caused by the rain or snow melting and penetrating into the glass. The water repellent coatings will not let water penetrate into the glass even in pouring rainstorms. It will create a hydrophobic barrier between it and water drops.

2. Water Repellent Coatings Last For Longer

The average life of a windshield is about seven years. After that, it can be damaged by the sun’s ultraviolet rays. The UV rays may make the windshields have cracks as well as peeling off; it will lead to water droplets being stuck to the glass. In this case, a water repellent coating is very useful to maintain your glasses in good condition. You don’t need to replace your windshield again and again because they will last longer with this product.

3. Water Repellent Coatings Reduce Idling Costs

Driving in rain or snow can be very dangerous. When there’s lots of moisture on the windshield, it tends to reduce visibility, which may lead to accidents. A water repellent coating can reduce the amount of time you waste idling. You will have a clear vision even in heavy rain and snow, and avoid any accidents caused by slippery roads and unsafe driving conditions.

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4. Water Repellent Coatings Have A Lasting Pleasing Appearance

Dark black spots on the windshield are very ugly to see. This is caused by oxidation, which will make the glass look dark and unattractive. When you use a water repellent coating, it will prevent any fading that may have occurred on the windshield. You won’t need to replace your windshield again and again because of its peeling off, cracks or chips.

5. Protect Car’s Paint

In addition to that, you can use this type of material to keep your car’s paint protected from scuffs and scratches caused by everyday driving. This type of material perfectly repels almost anything (including bugs) that might cause your vehicle damage.

How To Apply Window Repellent Coatings?

The application process is simple and you can do it yourself at home. With just a few steps, you can apply the window repellent coatings yourself on your vehicle’s glass.

Step 1: Apply A Lubricant To The Glass

Before applying the water repellent coating, you will need to first apply a lubricant to the windshield – this will help you with spreading, and it will prevent having any bubbles during application.

Step 2: Clean The Glass

Next, you must clean the glass with a lint-free cloth. The glass should be clean and free of oils or contaminants – this will help with the adhesion of the repellent coating.

Step 3: Spray Water Repellent Coating On The Glass With An Even Coat

You can now spray on an even coat of water repellent coating over the entire windshield, then evenly spread it across the surface.

Step 4: Wait For 10-15 Minutes

Once it dries, you may wipe it off with a clean microfiber cloth. You must wait for at least 15 minutes so that the coating can bond properly to the glass.

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By following these quick steps, you will be able to apply a water repellent coating on your glass and maintain its brilliant appearance. If you’re thinking of reselling your car in the future, this will help you get a good price for it.

Water Repellent Coating or Wax?

I first wondered should I use a water repellent coating or wax. Then here is what I found: Water repellent coating is the better choice in many ways.

A water repellent coating is a new technology that can enhance the car’s appearance and also protect it from the damage of normal driving. It helps to repel water, which is why many people like to use it on their paint job as well.

On the other hand, car wax will protect the car from rain by providing a barrier between your car’s surface and rain droplets. Wax basically creates a barrier between the paint and rain, snow, ice and salt.

However, a water repellent coating is also capable of doing that to some extent. Using a coating will prevent dirt from sticking to your car’s surface. It will repel dirt away so that you can easily clean your car more regularly.

Using wax instead of coating would make your job harder when washing your car in the future.

What’s The Best Water Repellent Coating?

If you ask me what is THE best water repellent coating, I can say that it’s Rain-X. Rain-X has been around since 1960s. It is proven to be safe and effective for all types of cars.

It will turn your car’s surface into a hydrophobic layer (superhydrophobic coating) that will make all water droplets bounce right off from the surface. I have personally used this and it works great.

You can spray it on your wipers too so they can clear your windshield more effectively on rainy days/night.
The best things about Rain-X are:

1. It’s long-lasting – no need to worry about having to change it regularly.

2. It’s easy to use – you can apply it on your windshield and does not require any skills or tools.

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3. It comes in a bottle with a sprayer nozzle that is very convenient and easy to handle. You don’t need to clean it every time as you want your windshield fresh and clean all the time (like other products).

Factors That Determine Windshield Treatment Longevity

The longevity of a windshield treatment largely depends on a number of conditions:

Type of coating – there are generally two different types of water repellents that you can choose from. Some companies use PDMS, while others use FAS. The latter is known to last longer than the former, but that’s not always the case. PDMS has been in the market for decades and is more popular among manufacturers. But if you’re looking for long-lasting protection, then FAS is your best bet.

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Another factor affecting the longevity of a windshield treatment is its thickness. Generally, a thicker coating is more durable than a thinner one. However, it all comes down to the quality of the product and this cannot be determined by merely looking at its thickness.

The UV intensity of your area – you may not notice it now, but as time goes by, sunlight exposure can deteriorate the windshield coating. UV rays can break through car windows and damage the windshield treatment. UV intensity also affects the lifespan of paint jobs and interior leather/vinyl surfaces.

Frequently Asked Questions (FAQs)

#1 What Makes a Good Water Repellent?

There are several factors that make a good windshield treatment. It should meet the following standards:

It must be effective in fending off water during rainy days and snowstorms.

It must be able to repel dust, grime and mud as well.

It must be UV resistant – scratches are one of the leading causes of windshield replacement. If it’s resistant to UV rays, then it will last longer than usual, even with minimal car cleaning.

#2 Can I Use These Water Repellents on the Inside Window?

Yes, you can. They are safe to use on interiors. However, it is not advisable for the following reasons:

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If there’s a lot of food on the carpet and around the seats.

If there’s a lot of dust in the air that can ruin the interior color as well as the integrity of your car’s surfaces. You might also have to wash your vehicle more frequently if you use this type of coating.

Some of these products may cause allergies from some people.

#3 How Long Does the Water Repellent Last?

Water repellents normally last from 3-6 months but the lifespan of these water repellent coatings depends on the following factors:

  • How you maintain your car – washing and waxing your car will help to extend its life.
  • How often you use your car – in-season usage will increase the need for frequent cleanings, while off-season usage will diminish the need for frequent cleanings.
  • How much you drive in bad weather – driving during rainy seasons can lead to a lot of water drops accumulating on your windshield.

#4 How Long Does it Take to Apply This Water Repellent?

It will take you about 15 minutes to apply this coating and the treatment should be applied once or twice a year (every 6 months).

#5 Is Rainx Bad for Your Windshield?

No, Rain-X will not cause any harm to your car’s windshield. It has been in the market since the 1960s and it is very effective even today.


A water repellent coating can help to give your windshield a nice hydrophobic layer that will repel water. This will make your car look great and protect it from scratches and cracks that can arise due to constant exposure to rain, snow, ice and salt. So, I can give a big YES to the question of do car windshield water repellent coatings work.