@Scalar, there is no active warming, just the christmas lights you see which give local warming. My absolute minimum so far was this winter about -9. I live close to the sea so my climate is much differend as it is some kilometers more inland (they had till -20degrC). I had some frost days, about 10 and most of the night temps were around -2 till -6degrC for one month. nowdays night temps are around 0.
@Damir, the little J.Chilensis is again without protection outside, picture made yesterday:

Here you see it at the right in pot, got alot of snow on his head this winter


@Trava, thats a Dicksonia Antartica, he's doing great, especially because he had hunderds of bees in de head last summer, they digged it out so im a little bit worried if he's gonna survive. I dont have birds, that thing is for cats, i dont like them in my (or other) gardens so they can go out whenever they want trough a little door into the cage.Some times there is a little bird which comes in but they never got out again

@Porat, sometimes i close the front part of it, if i get strong eastern winds in combination with rain/snow etc. Also i close it when the temps drop very deep like the -9degrC, the other side has just some bamboo so is always open (southwest part).
Thanx guys, hope i gave you the info you asked for.
Greets.