Question of the week: Should I bother with rain repellent for my windows?
Fri, 12 Jun 2026
Dear Honest John,
"I've used a leading brand of rain repellent on my car windows for about 30-40 years, plus various waxes etc for the bodywork. Despite the fact that the rain repellent doesn't appear to last as long as it used to, I still swear by it.
However, I recently moved with the times, and with the purchase of a new car, went over to ceramic coating for the bodywork. I find it very hard to distinguish which is the best product for maintaining the finish as they all seem to say they do the same thing, even with different names on the bottles from the same manufacturer (McLaren HydroSeal 82, and Mclaren Dura Coating 83 for instance).
But one thing they all seem to say is 'suitable for all exterior surfaces'. If that's the case, why am I bothering to use a seperate product for the glass? But to confuse matters even more, McLaren also produce a seperate product for glass. Is this just clever (but confusing) marketing? If there is any differance between these products, I'd be very interested to know what it is.
- AS
Dear AS,
Car care products that state they are 'suitable for all exterior surfaces' are generally accepted to be suitable for paintwork whether that is the body or the bumpers, but for exterior surfaces where paint is not present, such as alloy wheels, tyres or glass, it is sensible to use a dedicated product to ensure that its properties are designed to work with that specific material.
In the case of glass, there are a number of additional factors to consider which is why we would recommend using a specific product. Firstly and in particularly in the case of the windscreen, it is crucial that any product does not leave any streaks or residue that could affect the way sunlight or rain reacts with the glass and impacts vision.
Dedicated windscreen products are also designed to ensure that windscreen wipers sweep the screen smoothly without smearing or judder, as well as being safe when interacting with windscreen washer fluid.
If you choose not to use a dedicated windscreen cleaning or rain-repellent product we would recommend not using any other kind of sealant or protection on the glass.
