Today, I’m going to share what I believe is the best rain repellent for windshields. I’m also going to show you a surprisingly simple alternative that you may already have in your detailing arsenal!
Rain repellent products can be quite helpful when used on the glass of your vehicle. They make the surface much more hydrophobic which causes water to bead off (just like wax on your paint). Their biggest claim to fame is that rain slides off your windshield so rapidly at highway speeds that you don’t need to use your wipers. In my experience, that’s true. But it also raises the question:
Why are we so obsessed with not having to use our wipers anyways?
I mean, I could see rain being a big problem if we didn’t have windshield wipers. In that case, these products would be a necessity. But we do have functioning wipers on all of our cars. So why not just use them as they’re intended?
Bare glass vs treated glass
There’s two different schools of thought on this subject. Some people swear by rain repellent products, and others will never let them near their vehicle. I can understand both sides of the argument. Not all of these products are created equal though, so just because you’ve had a bad experience with one of the lower cost options, doesn’t necessarily mean they’re all bad.
Untreated glass will work just fine in most cases as long as both your windshield and wipers are kept clean. The only time you might have an issue is during those severe downpours where your wipers can’t physically keep up.
The most common reason why people avoid using coatings on their windshield is because they don’t like the way the wiper’s performance is affected. Many lower end products allow you to use your wipers less, but when you DO use them it reveals some side effects. And when the coating eventually wears out, things get ugly…
Some coatings make the window fog up easily and cause the wipers to leave smears or a haze behind. In my experience, this happens with the less expensive products more often than the higher end ones.
It’s very easy to tell which windshields have been treated with a rain repellent coating as soon as they get wet. Water forms tight little beads on coated glass while it sits in much larger drops when no coating is present. This makes it much easier to see through areas where the wipers don’t reach. It also means that these products are great for side and rear windows as well as moonroof glass.
Rain repellent coatings can actually extend the life of your wipers. You won’t use them nearly as often as you would with bare glass. When you do use them, the surface has less friction.
Different products, different results
There are quite a few rain repellent coatings available. RainX and Aquapel are the most popular. Many companies that specialize in ceramic paint coatings also offer products for your glass as well like Gtechniq, Optimum and Gyeon. Most of these are easy to apply – simply wipe on and wipe off.
RainX is an entry level product that can easily be found in local big box stores. This is a cost effective way to repel water from your windshield. RainX has a large number of loyal followers and they’ve even extended their product line to windshield washer fluid and wiper blades. These are designed to work in unison with their original coating. RainX works pretty well but won’t last as long as other products that are available.
I can’t say that I’ve tried Aquapel, but I’ve heard lots of people talk about it. From what I understand, its place on the market is between RainX and the higher end coatings. It’s a bit harder to source and seems to be sold mostly by auto glass shops and car dealerships as an upgrade. Users have reported that Aquapel lasts longer than RainX in most cases.
Since writing this post, I had a chance to try Aquapel. I applied it outdoors on a daily driven car. Even though I cleaned and dried the glass thoroughly, applying Aquapel was a nightmare. The product flashed way too quickly and dried to a haze almost immediately. It was extremely difficult to remove and I eventually had to take drastic measures to do so. I was able to remove most of it with glass cleaner and some heavy scrubbing but in the end, this rendered the coating useless.
In all honesty though, I don’t blame Aquapel for the problems I experienced. You see, I was applying it outdoors on a very humid day. Aquapel specifically states “Do not use in temperatures colder than 50º F or hotter than 90º F or in excessively humid conditions.” So really, it was my fault for not following the directions.
The thing is, other products don’t have these limitations in the first place. Unfortunately, that’s still a strike against Aquapel. This product seems to be common with dealerships, auto glass shops, and detailing shops which makes sense – they can control their indoor climate.
Applying this outdoors as a hobbyist or mobile detailer doesn’t seem to be mentioned nearly as much. Is that because of the humidity issue? Possibly. I still have another application left so I’ll be attempting this again on the same car in the future. Hopefully, doing it in the proper conditions will render better results. Until then, I’ll be sticking with the other options mentioned in this article.
Nano coating companies
Products from Gtechniq, Optimum and Gyeon are likely the best performing and longest lasting options out there. They’ll also come at a price premium. These companies specialize in coatings that bond chemically to various surfaces so they’ve certainly got science on their side. Most of these are readily available at any detailing supply store and unlike some of their paint coatings, these are sold to the general public.
This article was originally posted on Canadiangearhead.com. If you’re reading this anywhere else, it was stolen and reused without consent.
Which of these is the best choice?
A bottle of RainX will go a long way, but you’ll need to reapply it often. If I’m going to purchase a specific rain repellent product, I’m probably going to go straight to one of the higher end coating companies. Competition is tight in that industry, so they’re always coming out with new technology. That being said, I might just skip out on buying these products altogether in the future…
What happens when rain repellents fail
This is something that’s not talked about all that much. This is a big factor in what product (if any) you choose to go with. Any of the above mentioned options will eventually wear off and need to be reapplied. It’s right around that point where performance goes from “better than bare glass” to worse. Much worse.
Once the coating begins to break down, it becomes very inconsistent across the windshield. It doesn’t just stop repelling water – in many cases, it also creates random sticking spots for your wipers. The result? Your wipers start squealing and chattering.
This can be incredibly irritating, especially on long drives. The worst part is, you tend to forget about reapplying your coating until it rains again and you turn your wipers on. Since you can’t apply any of these products in the pouring rain, you’ll have to withstand yet another aggravating rainy drive until you’re able to deal with it properly. This can be a painfully repetitive cycle if you’re a forgetful person.
What variables will affect how long a product will last?
1. How well the surface is prepared
First and most importantly, the way you prepare the surface before applying a product makes all the difference in the world. Your window needs to be perfectly clean for the coating to bond properly. This step is important whether you’re applying a rain repellent or not. Clean glass will always outperform dirty glass with contaminants stuck to it.
The ideal way to prep your windshield is to clean it first, then claybar it. This will help to pull any contaminants off that may be stuck in the glass. For those wondering, yes, it’s perfectly safe to use clay on your windows.
Next, you’ll want to polish the surface either by hand or machine. This will help to remove any stubborn water spots or minerals, otherwise they’ll be trapped under the coating. After polishing you’ll want to clean the glass one last time to remove any remaining polish before applying your coating.
2. The age of your windshield
A rain repellent product will likely last longer when it’s applied to a brand new windshield rather than an old one. Small rock chips and scratches will affect how well the product can bond to the glass.
3. Where your car is parked
Whether you park indoors or outdoors will make a difference in the life of your coating. Sitting outside in the hot sun will surely break the product down quicker than if it’s stored in a garage.
4. How often you use your wipers
This is a big one. Every time your wipers drag across the surface of your windshield, the friction will scrape some of the coating off. If you drive mostly on the highway where you can avoid the use of your wipers, your product of choice will last much longer. City driving will require the use of your wipers at slow speed regardless of what coating you use.
The absolute worst thing you can do is turn your wipers on when the surface is dry and dirty. That’s like taking sandpaper to your windshield!
Tip: If you must use your wipers, make sure the glass is sufficiently wet from the rain before turning them on, or give it a shot of washer fluid first.
Gtechniq G1 ClearVision Smart Glass – An Honest Review:
I didn’t actually buy Gtechniq’s G1 glass coating on purpose. I purchased a complete kit from them that included their ceramic paint coatings as well as other products to protect nearly every surface of a vehicle. My plan was to test Gtechniq’s products on my daily driven 4runner.
G1 ClearVision Smart Glass (sheesh, could you come up with a longer name!?) comes as sort of a mini kit. Gtechniq includes a bottle of G2 Residue Remover and a few applicator pads along with the bottle of G1. This might seem generous, and it is, but I think they did this to make sure people apply it properly with the right products.
Application is important and doing it incorrectly could be the difference between them getting a good review or a bad one. Guiding people in the right direction certainly helps the overall image of their product.
Gtechniq claims G1 ClearVision:
- has 1 to 2 years durability
- Improves wet weather visibility helping to improve safety and eye strain
- Makes ice, bugs, tree sap etc. much easier to remove
In the past year I’ve found all of these to be true, except for the durability. Gtechniq later goes on to make another claim, saying it should last for 30,000 miles (48,280 kms) under regular driving conditions. That to me is absurd.
There’s way too many variables that will affect how long a coating lasts, not to mention the windshield isn’t even a moving part of the car. Measuring a tire’s life in mileage makes sense. Giving a windshield coating a mileage rating is just plain silly.
I purchased the 15 ml size bottle. In general, I’d say that’s enough to do all of the glass on an average sized SUV, with maybe enough left over for a light 2nd treatment for the windshield later on. I applied 3 coats on my windshield and a single coat on all of the side and rear glass as well as the moonroof.
I won’t bore you with the details of this. Nathan from Cambridge Autogleam made a great video explaining how to apply G1 ClearVision properly. It’s worth noting that he’s an accredited Gtechniq detailer and is authorized to install their professional products so he definitely knows the proper way to do this. The only thing I did differently was I used Meguiar’s M205 polish instead of Gtechniq G4.
Aside from the durability claims, my experience with G1 Smart Glass has been a good one. My vehicle sits outside year round and I drive it in all 4 seasons. This coating does exactly what they say it will. It repels water better than any other product I’ve used. Water begins to slide off at as low as 60 kph.
Any contaminants that may be hard to remove from the glass normally, now come off with ease. I’ve noticed some haze from the wipers at night time when the street lights glare on the windshield, but nothing terrible.
I was able to come close to the 1 year durability mark, but unfortunately performance of the coating dropped off a bit early. My results were more like 9-10 months and 6,000 kms (which proves how ridiculous the mileage claim is). The majority of my day to day driving is in the city at slower speeds. That means that regardless of what rain repellent product I use, I simply can’t avoid the use of my wipers.
That was the biggest reason for G1 ClearVision not lasting longer, especially in the winter months (scraping snow off). In contrast, any other lower end product would have likely only lasted a matter of weeks under these conditions.
The nice thing about Gtechniq G1 is that when it did finally begin to fail, I still didn’t experience any issues with my wipers squeaking or chattering. This alone sets it apart from its competitors.
This is an expensive product. The initial cost of a bottle is similar to other rain repellents, but this one will last you for 1, maybe 2 applications while a bottle of RainX could last you for years. G1 ClearVision offers better performance and won’t need to be reapplied nearly as often though.
The fact that G1 ClearVision is built with the same technology Gtechniq uses on their nano paint coatings is an obvious bonus. I believe it’s worth the price if you’re a fan of using rain repellent products.
But what if you aren’t?
The other option
Now, for the off-label use of a product that I’ve been hinting to throughout this post. The main goal of a rain repellent coating is to make the surface slick and hydrophobic. Many of us already have products on our shelves that do just that…
Most paint sealants and spray waxes are perfectly safe to use on windows. Their same water beading characteristics work on glass the same way they do on paint. They won’t bond to the glass as well though, so they won’t last as long. But we already know that some rain repellent specific coatings don’t last long either!
If you need to reapply whatever product you put on your windshield often anyways, it might as well be one that you already have and use. That’s an unbeatable value.
No, these won’t work as good or last as long as the higher end rain repellents. They also won’t break down and cause your wipers to chatter or squeak either, they just slowly disappear. When that happens, you can quickly clean your window and reapply it in 5 minutes.
Want to know 8 other genius off-label uses for spray wax? Check out this post:
This is a great option for anyone that’s against rain repellent coatings, and one that I personally use on my MR2. I can count the number of times I use the wipers on that car per year on one hand, so I could never justify the use of a higher end product.
Whether you’re for or against rain repellent products, the most important thing is to keep your windshield and wipers clean at all times. Tree sap and grease will surely smear all over your window regardless of what you use.
In my opinion, if you’re interested in buying a rain repellent coating, step up to one of the higher end companies like Gtechniq. If you don’t want to spend the money, just use a paint sealant or spray wax rather than a cheaper product.
Tim is the creator of Canadian Gearhead. His experience with auto detailing and working for Toyota shows through all of the articles posted here. He runs the Canadian Gearhead site and YouTube channel full-time now and currently owns a 2007 4runner, 2006 Tacoma, and 1991 MR2. Read more about Tim: