DIY fixed temperature alarm

I hadn’t seen anyone else post this here.

I created my own low temperature alarm for my home for when I am away. Using a KSD 9700 15°C bimetal thermal protector and a contact sensor module. I picked up a few from eBay for a couple bucks each. The protector switch closes on temp drop at approx 10°C and opens on temp rise at approx 15°C. If my furnace fails during cold weather I will receive a notification if my house gets too cold. I also connected the contact sensor module to two AA batteries so I don’t have to worry about the battery failing and won’t need to buy anymore of those expensive watch batteries.