Beekeepers have argued over the merits of insulating hives for winter for many years. I personally do, if only to help reduce winter fuel consumption. It is apparent from my one polystyrene hive that fuel consumption is less in winter and the colony stronger in spring than wooden hives, although this is not enough statistically to draw any real conclusions.
Here’s a link to a ‘paper on insulated hives. http://www.norfolkbee.co.uk/useful-documents. See the INSULATION HIVES link.
In addition, if you search for a pdf of ROB Manleys Honey Farming, he describes experiments where insulation does not help!
Confusing or what!