Hi Yoshi, you are intending to spend alot of money on a pretty looking property, personally you will not go wrong listening to Scunner and Eric, as this is going to be your home, and if you don't get it right before purchasing, you could have to live with your mistake for many years before you find a buyer allowing you to move on.
Why not rent a property in Uzumlu for a few months in the winter, End of November to the beginning of March, this will be the cheaper and safer option, especially as you are concerned regarding the cold.
I personally do not feel the cold, and quite happily have the windows open all year round here in the UK, home in the UK heat up quickly once the window is closed, however, when we lived in Turkey I would not dream of doing that in the winter at night and some days, once a property is cold in Turkey it will take longer to warm up.
Scunner does know about underfloor heating, he had this in his villa, we are all trying to help and save you money in the long run.