I’ve been tinkering with making a long dream of mine a reality next year: To drive around the globe and the 5 continents.

I want to make sure, I’ll have backups of certain systems and want to know what to expect if I had to have the rear heatable glass run all night long (conventional wire heating), especially if for longer periods, like several months.

Do the heating wires tend to burn out or wear out otherwise? Is there a risk of overheating or maybe fire presuming interior temps up to 19 C°?

How many hours one may expect of such hearing systems to last?

  • Welcome to Motor Vehicle Maintenance & Repair! Commented Oct 2, 2022 at 15:08

1 Answer 1


I don't think there's any real answer here. You can expect them to run until they don't. Usually they do not burn out, even if run continuously. That's mainly because they don't really get too hot. They just bring the temperature of the glass a little above the dew point, probably no more than 100° F (I don't know for sure, just know it isn't much more than "warm" to the touch). I've experienced window defrosters work for 20+ years, so they will last for a long time. These are designed so there is no fire risk, so running it for long times should not incur any issues.

As an aside, the defroster "wires" are nothing more than painted onto the glass. Usually the only time I've seen them go bad is if they are scratch and no longer make contact. You can find repair kits for this which basically reattach the broken ends together by painting on a very thin line in between the break. By doing so, you reconnect the connectivity and that portion of the defroster works again. You might consider getting a kit like this to help you along the way.

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