The room has got no heating, wich basically is not necessary for
wintering my domestic species.
The main issue is the protection from cold winds and too much
moist while warmer winter-periods.
The climate in this room is relativly constant in spring.
I mean the temperature rises not that extrem (like e.g. in glasshouse or so),
when the first sunny days are spending theire energy to the habitat.
The trees will not sprout too early, and that will decrease the threat
of frost-damages ...