Yes - you can have too much insulation ...
Yes, of course, there are limits. But polyhives have far more insulative properties than timber (with 18/19mm thickness). Ask that small cohort of one, with c.2000 colonies, perhaps?
Common sense should prevail, so not going to the ultimate extremes. How many colonies survive the winter with no insulative protection whatsoever? OK, Mary in Warwickshire had a colony unprotected on two 'sides' for two winters, but show me any that survive with no protection at all!
Right, so we have no insulation equates to death of the colony;I know that 5mm ply is good enough for bees to survive the winter; we know that 18mm timber is good enough for many to survive fairly easily (with extra insulation in the form of outside frames); we know, from the cohort of one, that polyhives with 40mm walls are better than timber; so exactly how much ESP is too much? 100mm, 200mm, 300mm?
I don't know of anyone who goes to those levels of insulation. So which would be the optimum between the normal 40mm thick walls of a polyhive and 100mm thick walls. Anyone know?
No? OK, lets settle on 40mm of polystyrene as a good level of insulation? Then insulating all timber hives to the same level is simply the common sense answer - just like the 'cohort of one' did when changing from timber to polyhives. QED?
I think so. Simple. Insulate all hives to the same level as the standard polyhives presently available. End of story.
RAB