Here in north Florida, we are expecting 2 nights of hard freeze, down to the mid 20's . My buddy, who got me into bees and I, just finished making a bunch of insulated hive bodies and supers. We took our normal empty hives and supers and attached with pin nails and glue, 2 inch closed cell foam, with something like a T-111 siding. This product can be special ordered from Home Depot or Lowes.
This product comes with the foam already attached to the siding. We cut the siding and foam on a table saw. I think it was kind of like cutting crown molding, as we had to get the corners right. I plan on using these in the upcoming season , year round, to keep the girls cool in the summer and warm in the winter.
My 2 hives both swarmed and left in late July. My buddy still has all 11 of his, no swarms. He thought of the idea and tried it out about a month ago on just some of his hives. They are all side by side, and he said that the insulated hives are by far the most active and healthy. In anticipation of the upcoming freeze and since today was in the 70's, he changed out the rest of his hives for the new insulated bodies. He just took the frames out and transferred them to the new insulated bodies.
I don't know why I don't see more info on insulated hives. I see you can purchase an all styrofoam job from dadent, but I would suspect it might be weak. I would rather take a regular box and add insulation around it. ( of course, I am a total newbie, so....)
you will find a lot more on uk beekeeping forum.