The main problem I see in highly insulated hives in the winter is overheating during a warm spell. The bees make heat to keep the cluster warm and that does warm up a foam hive. Iíve seen hives in the upper 80s when itís 32F outside. Problems start to occur if they get too hot in the middle of winter in Michigan. The top vent/entrance in my full sized hives seems to prevent the excessive heat while still providing an insulating blanket for the bees. Despite a common beek belief, a small hole in the top of an insulated hive is not going to let all the heat out. Just like a small hole in the top of a human house doesnít let all the heat out.
No they dont overheat.. had mine with a bottom entrance below floor level , no top entrance, elaborate sealing box to box, no mesh, levels of insulation beyond yours Bluebee,
30C in shade external temperature, hive in full sunshine no bearding.
The honey ripens quite fast though
If let them get on with their own style of Aircon they can control it themselves., when the only heat input is through the the entrance and their body heat