With a heating element in your wine cooler cabinet, the temperature is kept stable in cool environments.
A wine cabinet with the heater can basically keep the cabinet 8 degrees warmer than the ambient temperature.
These wine fridges can work in environments as low as 0°C, where they can deliver a maximum temperature of 8°C.
If you want to make sure your bottles are stored at 12°C, make sure that the ambient temperature is never below 4°C.
If you wish to install your wine cabinet in a room where the room temperature can be lower than the temperature you have set the cabinet, you will need to have a wine fridge with a built-in heating element.
As an example, you can place the wine cooler in a room without heating and the wine cooler cabinet set to 12°C. This is possible provided that the room temperature is never below 4°C.
Generally, it is preferable to maintain a diffence no larger than 8°C between the set temperature of the cabinet and the room temperature.
Avoid placing the closet in a room where frost may occur, as most wine fridges will not be able to function.