Heat & cool blanket...

[Hauntedyards]

Any thoughts on these? Could this be adapted to fermentation? Says you can select any temp between 50f and 113f and will heat or cool depending on ambient.

 

[TalkingGoats]

https://www.homebrewtalk.com/f14/hot-cold-blanket-fermenting-235510/

Talking about something like this? Or a Peltier kind of deal? I think both would be less efficient than a fridge, but cooler. No pun intended.