Rain-X 630046 Interior Glass Anti-Fog, 12 oz. - Prevents Fogging of Interior Glass and Mirrors, Usable on Both Automobiles and Marine Vehicles

The heater/defroster in my car stopped working and it was almost impossible to get the windows to defog in the morning. I cleaned my windows really well, applied a decent layer of this stuff, let it dry, then used a clean paper towel to buff the film away. Worked like a charm! My windows were crystal clear this morning! Worth every penny.UPDATE: one week later and there seems to be an odd film on my windshield. It didn't show up until about 2 days after using this stuff. My driver and passenger windows do not have the film but my windshield does. I'm going to clean it a few times and try to apply this stuff again to see what happens. Not sure why it worked so well on the other windows but not my windshield! Will post another update after I give it another shot.ANOTHER UPDATE: it's been about 2 months since my last update and I think I've got this stuff figured out! After cleaning my windshield again really well to remove the film, I reapplied this stuff the same way I did originally but buffed twice as much as the first time. They were crystal clear for about a month until it started to wear off! So I just did the same thing and it lasted about another month.So if you clean your windows REALLY well prior to applying this stuff, then buff the film off REALLY well after applying, it should last about a month before it starts to wear off and you slowly notice it fogging. This is the most effort I've ever put into a $5 Amazon product review but I hope it helps someone lol!

Yesterday was the first day of the season where my windshield fogged up as it was raining. I applied this product as directed and then immediately went on a drive. I did not need to defog my windows at all. There is a slight haze when there is a big humidity change between inside the car and outside but you can still see just fine. In the photo you can see the difference where the product was not applied at the bottom of the windshield.

I found this works great to prevent fogging, especially for the side and rear windows. You may find it will leave a residue that can annoyingly obscure your sight through the front window so be certain to wipe down the windows. Rain X also works great on bathroom mirrors and lasts about one month with each use.

I've now tried close to a half-dozenl spray products such as this - mainly to try and keep fog off of bathroom shower mirrors. I've now tried 5 different brand names, including this more well-known Rain-X interior anti-fog spray.In each case - again, I happen to be using it in a shower stall setting - the effects of keeping steam/fog away - lasted for only a day or several days at the most. It actually became quite frustrating really. I applied as directed and when I first tried taking a shower, the first day I was screaming "whoopee," because I thought I finally found the solution to constant fog on the mirrors (which I use for shaving in the shower). And the shower mirrors I use (I have a huge walk-in shower) are never even touched by water. However, it was all to no avail, and the Rain-X only lasted only for several days before the fog began coming back with a vengeance. Sure, I tried applying it again - but again, that only lasted a day or two more.Now, from what I understand (and based on some past use with cars), this Rain X works fairly well for keeping fog off of the inside of car windows. But if you're thinking about using it to keep fog/stream off a shower mirror (even those that do not get water on them), just forget about it.As an aside, if you're considering purchasing a separate fog-free shower mirror, rest assured I tried those also. Many of those inexpensive Asian-made fog-free shower mirrors (as they are called) being sold in droves on Amazon and eBay, are nothing more than conventional mirrors with a similar anti-fog solution sprayed on at the factory. The end result on those is that after several days to a week, the solution wears off and the fog begins to form also.So there you have it. These sprays are good for car windows and car mirrors, but if you're looking for a solution that prevents steam/fog in a shower setting - these products won't last for more than a few days. So keep that in mind...Still searching for the right solution for a shower setting that actually works long term.

This is an amazing invention. I drive a classic car that doesn’t have a front window defroster, and this saves me from having to spend countless mornings, wiping the fog from the inside of my windshield. In fact, I use it on the inside of all my windows and I have perfect visibility, no matter the temperature or humidity of the outdoors.

The issue with this anti fog for the inside of the windshield is it is very hard to buff to a clean streak free shine. I drive a converted 4WD Mercedes Benz Sprinter van and at night, if it is cold outside, the windshield still fogs up. It does not work as intended. Since the windshield is so large, it takes forever to wipe it off. It will leave streaks no matter how clean the windshield is. After I "finally" got it buffed out, it still leaves streaks that you can see when driving in the sun. At night when I put the shades so no one can see inside the van, the next morning it is completely covered with condensation. It is a waste of time and money and does nothing to keep the fog from building up on the inside of the windshield. In fact, it actually makes it worse. I would not recommend this product for anyone as it does not do what it is advertised to do. It is an exercise in frustration. And you will spend a long time trying to buff it out for something that doesn't do what it is advertised to do. Buy at your own risk