When I have looked at the various designs of poly hive, it seemed to me that a lot of the designers were more concerned with structural integrity and saving material than in the absolute best thermodynamic performance. There were ribs clearly intended to stiffen the sides but that left large areas with comparatively thin poly walls. Poly thermal performance is no different to that of other materials - the thicker the better; thin walls lose more heat. Some designs have lifting hand-grips that are far bigger than they need to be and these thinner areas lose heat that is entirely foreseeable and unnecessary. Maybe the designers of Finman's newer hives have concentrated on the best thermal performance rather that structural integrity and material cost-saving.
If DerekM is about, he might be able to offer a better explanation.
My next project is to build a PIR hive with 30mm thick walls but using a 30mm thick deep roof/cosy during the winter to help maintain suitable brood temperatures - all based on ideas gleaned from DerekM's research.
CVB
Those polyhives have tested in very cold countries tens of years.
Two producers in Finland are real top professionals. Another has 2000-3000 hives, and another has 1000 hives. But the model before them was Nacka hive, and it is still splended
in -30C winter weather. We have lots of professional beekeepers in Sweden and in Finland, who have used polyboxes tens of years.
I wonder what new British beekeepers can offer to that issue?
Those guys produce honey. Hives are not toys. Winter food lasts from September to May, because insulation is good.
Tools and furnitures must be handy to work, and insulation has not been problem in beekeeping during last 20 years in our country. That is why all beekeepers use insulated hives in Finland.
Derekm has much to do among British beekeepers, who do not even know, what is true winter. He can start to manufacture those new generation hives, if he is serious in his teaching. Poly prices are really good UK, and he can run prosperous business.
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