Rain-X Is No Longer the King of Windshield Rain Repellents

A series of simple tests show the legendary Rain-X windshield repellent has some stiff competition. But it's still among the greats.

two bottles of Rain-X windshield water repellent

Brian Silvestro

By: Brian Silvestro

Apr 27, 2024 at 9:00am ET

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Rain-X is a household name. Since the 1970s it's been the go-to windshield water repellent for drivers everywhere, promoting outward visibility even in the thickest rainstorms. But these days, Rain-X faces some serious competition.

In a series of comparison tests between 10 different windshield water repellents, the Project Farm YouTube channel finds that Rain-X is no longer the best hydrophobic product in the game. But it's still competitive, something that can't be said for more than half of the other products tested.

In Project Farm's tests, just four brands—Gtechniq, Aquapel, Gyeon, and Rain-X—kept their hydrophobic properties after being subject to car wash soap and windshield washer fluid—two things you might normally expect to come in contact with your windshield. The six other brands—Adams, Cerakote, Invisible Glass, Chemical Guys, 3D, and Debaishi—virtually stopped working after a quick wash using car wash soap.

Of the four top brands, Aquapel and Gyeon were the quickest to have water removed from the glass when subjected to a a blow dryer, at just 1 second. In this test, Project Farm was attempting to emulate the wind forces acting on a car at roughly 40 mph. Rain-X and Gtechniq tied for last, at 3 seconds.

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Where Rain-X lost out most was in Project Farm's warm temperature exposure test, where each piece of glass is kept in a dishwasher and exposed to hot water spray for 2.5 hours. This is an attempt to emulate rain on a hot summer day. While the other three brands held their performance after the test, Rain-X's effectiveness decreased.

That's not to say Rain-X isn't still worth it. Considering it was by far the cheapest product of the bunch, was among the easiest to apply, and held onto its effectiveness throughout most of the tests, we wouldn't fault anyone for using it on their car. But if you want the absolute best product around, it's Gtechniq's G5 water repellent coating is it, at least according to Project Farm.

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