Numerous horrible ZooMed products!?!

I've had a similar problem with the ZooMed Power Sun light bulb, though not quite to the same extent - I had one stop working after about 3 weeks, but the replacement has been working fine now for about 10 months. I don't blame you for being mad about those breaking, those light bulbs are not cheap!

I believe my current UTH is also a ZooMed (which I'm using temporarily until my Animal Products cage with Flexwatt heating arrives) and it works perfectly fine when it's regulated by my Herpstat thermostat. Maybe I missed it somewhere, but I can't tell whether or not you are using a thermostat with your UTH. If you do have a thermostat, then there is likely something wrong with either the UTH or the thermostat. If you don't have a thermostat, you should get one, no matter what kind of UTH you use.

I've used pet store heating pads in the past, and I hate them.
I had one that wasn't regulated by a thermostat make a buzzing sound. I was just testing the tub temps, no animal was in there. It eventually sparked. I have no idea how the pad sparked as there were no exposed electrical wires, but it did. That thing immediately went into the trash.

And Aaron's right. Zoomeds or any heatpads can achieve 130+ degrees easily if it isn't connected to a thermostat.
And warmer the room, warmer the unregulated heat pad is going to be too.

So before buying any new heating pad, buy a thermostat first. A thermostat is a reptile keeper's most important piece of equipment.

Thanks everyone :) I appreciate all the info and advice!