Question

Is there a reliable freezer temperature alarm solution that works with SmartThings? I've tried the multipurpose sensor in a freezer but it goes offline when the battery gives up due to the cold.  

Answer 1

A quarter on top of a glass of ice will tell your if your freezer lost power long enough to thaw. A power monitor could warn you right away if you lose power.  

Answer 2

For zigbee devices it is hard to send from inside a fridge. they need a lot of energy. with 433 mhz it works better