VERY possible. If they're not sending out a pure sine wave, that indicates a really bad problem on their end - for instance RMS measurements would be way off. Also most places have 240vac going in, and if the ground/neutral isn't solidly connected all the way, you can get really weird problems (like motors running noisy or hot, and so on). We had that problem and blew light bulbs until it was found and fixed - one leg was high, the other too low a voltage.
I find it strange that soldering irons aren't lasting. When I was in business (industrial electronics repair), I soldered all the time. I'd go through tips on a regular basis, but the rest of the iron kept going - a cheap iron, well, I've got one that I've had for many years (admittedly, I didn't use it on a daily basis and haven't used it in some time). I used a propane iron in the field, and did go through those rather regularly, maybe once every couple of years. I think that you might be onto something because of how quickly they go bad - a bad waveform could possibly do that. If the peak voltage was high, but the actual area under the curve (overall) being low, it could wear out the elements but not get hot enough. I've seen something similar to that in the past (on a plasma cutter/torch).
I'd be real interested in seeing the waveform.
Right now I'm using a temperature controlled iron from Radio Shack - purchased in 2012. I had to replace the iron itself because of bad internal connections once (I suspect factory defect), but other than that, no problem. I have a small 15w pencil iron, and my old 150(?) watt monster (very old and I've had it for several decades - great for coax connectors and ground plane connections).
Bob
N4FBZ
