Budget Temp sensing for a freezer?

Hello, I want to put a sensor in my chest freezer so I can use it to alert me if the temperature starts to rise when it shouldn’t. What is the most cost effective device for this purpose. I didn’t see just a simple temp sensor in the product list.


A cheap contact sensor works, you might find some Iris V2 sensors on Ebay they work well for that.

Many devices have built in temperature sensors. The $14 SmartThings button is one of them. I don’t know how any of them would hold up to freezer temperatures but it might be interesting to find out!

I have the V2 Iris sensors in my refrigerator and two freezers. They are even set up with the magnets to tell me not only if the temperature is rising but if the door has been left open. It can be a bit tedious to set up because they are on the inside of the door, but if you find the right spot and go through a little trial and error fitting, it is worth it.

I originally had the newer SmartThings sensors installed for this purpose but the coin batteries ran low and did not last long at those temperatures. Having come from Iris, I knew that those sensors which use a CR2 battery would hold up. They do show a lower battery percentage at low temperatures but they continue to work for a long time.

You can set up to get alerts for temperature rising above a certain temperture and the door being left open for an extended period of time.

1 Like

Thanks for the input. I will go with the Iris V2 contact sensor I think. I had done this once before and it worked pretty well.