I have some concerns from looking at the reviews on Amazon. At least four people have posted that the controller portion overheated (they have photos of scorched controllers). I do read those with a grain of salt (as I do all reviews that seem to be outliers) because four out of 12,000 seem statistically safe. Also all those reviews were from 2016 which makes me think that they have since addressed this safety concern. I do wonder if that is why they say they are only making versions with an auto-off feature.
I’m assuming you are talking about the heating pads, not the heater that was mentioned before, so I’ll respond accordingly. Those reviews were pointed out to us on the Heating Pad thread, but as the poster said, she noticed that those reveiws weren't even for the Heating Pad that we recommend. Another member called Sunbeam directly and was told there were no plans to discontinue those pads and go to Auto Shutoff Only models. The reviews were listed as being for a Pad with a different serial number altogether, a Pad which the Sunbeam rep said had been pulled. And Sunbeam does indeed still make a Pad without any bells and whistles, and which does not have auto-shutoff, at least as of now. The pad I strongly recommend, the Sunbeam X-Press Heat, allows the user to set it to “Stay-on” so I doubt that if a Pad staying on long term caused serious overheating issues in the controller was an issue, it would still be on the market.
I always, always remind potential users of this system that ANY electrical device, from a coffee pot to a phone charger, can overheat. From the moment something is plugged into a wall, it carries an inherent fire risk. Shoot, wiring inside walls can cause fires even with nothing plugged into an outlet. I caution folks never, ever to use an old Heating Pad they may already have, but to spring for a new one if they want to use either Mama Heating Pad or @aart’s pseudo- Heating plate.
Older pads which have been rolled or folded up and stuffed in the back of a linen closet somewhere, while relatively safe to use on our aches and pains, are not safe enough to be plugged in, turned on, and then left to run for a few weeks out of sight of the user. Rolling, folding, and being shuffled around, possibly stored with stacks of heavier things on top of them, may have developed minute cracks or weak spots in the fine wire heating elements, causing shorts and/or overheating. If we are sitting with that pad on our shoulders or backs, we can tell pretty quickly by feel or a smell that that pad has an issue. If it’s out in the coop or in a brooder in another room, those initial signs wouldn’t even be noticed until it’s too late. So use a new pad, store it laid flat, and never, ever roll or fold it.
When it comes right down to it, heating pads are designed to come into direct contact with humans, fabrics and upholstery. Can they fail? Of course they can, and only a fool would say otherwise. But plug in and run a heating pad, then plug in and run a heat lamp. Which one will you touch directly or pick up with bare hands, even after just minutes? Yeah. That’s why I’ll take my chances with a heating pad every time. And if I need any further reminder, there’s the burn scar left on my little granddaughter’s arm from a heat lamp. She is the reason I decided there HAD to be a better way.