Thank you for your input.
I'm tempted to go this way:
digital temperature sensor: https://www.adafruit.com/products/642
I've been using the library RPi.GPIO, according to Eben Upton's book (R Pi user guide), so I 'm not familiar with GPIO zero library. I noticed that no resistor is used with the GPIO zero example you linked to. I'm confused: Doesn't that create a short?
For AC control:
I'm going to play it safe with this: https://www.adafruit.com/products/268
Let me know your thoughts on my approach. (Basically following the adafruit lessons on temperature sensing and AC control, using their digital sensor and power tail ac switch)
My main concern/ question: This is pretty prefab out of the box. I like that for AC control, to keep my family safe, but for temperature sensing I'm wondering how hard it is to use an (analog) thermocouple with the MCP3008. How do I buy a food grade thermocouple?
Thank you so much!