Looking for an electronic geek

[hktraveller]

What is it heating or cooling?

Both possible (Can be set). But voltage control is for the Peltier and for cooling only.
For heating I use a heating foil and always 12V with only on and off. (Overlooked the confusing possibility of a sensor at the heating plate without mentioning.)

[100LL]

What I meant is if it is heating tee and cooling beer or what you use it for?

[hktraveller]

What I meant is if it is heating tee and cooling beer or what you use it for?

The initial necessity where I started was temperature control for fermenting sourdough for rye bread. There I need 23 degrees that require cooling in summer, 26 degrees that I usually set the aircon at and 32 degrees that require heating.