Product report: Rain-X interior glass treatment

One energy waste is having to run the defogger to remove interior glass condensation. Many defoggers run the air conditioner to dry out the air that blows against the glass and that takes energy. Unfortunately this is when the ICE is cold and inefficient so there is a double price to pay. If we can avoid interior glass fogging, we can avoid this energy waste so this is a test report on Rain-X interior glass treatment:

It works but it takes a little work. Two days ago, I left the windows cracked to let out the solar heat but a storm came up and 'dampened' the interior. Last night, a cold front came through and it was in the high 40s (F) this morning. A damp interior and cold temperatures means window fogging.

I applied the Rain-X yesterday morning to both the driver and passenger sides. However during the day, I noticed the 'Rain-X' haze. At every stop, I would dry-wipe the glass with paper towels to reduce the Rain-X haze. Last night, I could tell the passenger side needed the same effort but it was raining as the cold front came through so I left that side alone.

This morning, the driver side was clear in the main area. Around the edges, the water had condensed into that opaque mass that normally requires a defroster to clean up. The passenger side had some splotches but the driver side was in good shape and no defroster was needed. In fact, as I drove into work, I saw five 'droplets' trail down the driver windshield glass. The water had condensed but the Rain-X treatment kept it from forming the hundreds of thousands of small droplets that make a window opaque. Even as I drove in and the 'shaded side' glass condensed a fine fog, the driver side remained quite usable without defroster.

Overall, this product works but it is very important to wipe clean the Rain-X haze. I didn't do that for the passenger side and that side was marginal. I would have needed defroster if that had been the state of the driver side.

Now the glass is not 'optical' quality with Rain-X, there is a slight haze and the suggestion that something is on the interior surface. However, it is clear enough that fuel wasting defroster is avoided.

Bob Wilson