> One practice that I would like to hear more about, is the use of a thin > (8 mm?) insulation consisting of 2 polyethylene bubble sheets, bonded > with aluminum on the outside. It makes a pretty durable, flexible and > compact insulation that is claimed to have an insulation R value of 12, > the same as 4 inch thick batts of glass fiber or rock wool. It's more > expensive (50 cents per square foot?) but should last longer and be much > more convenient to use and store. I've been told there are some (a few > hundred) in use (for 4 packs) in the Alberta Peace, and that they were > OK last winter. > > Have Allen or Eric heard any more details about them? Jean Pierre was doing something with this stuff too, I think. I haven't heard anything yet. I think the cheapest, and most ubiquitous wrap - other than homemade 6 mil plastic and fibreglas wraps are the Inland plastic wraps from Inland Plastics in Drumheller, Alberta. They are also very tough and long lasting. I just bought another 110 of them - enough for the 440 hives that had received my alternate treatment last year. They seem to work well and last forever - some of mine are 15+ years old and are just like new in spite of often being left out in the summer sometimes and laid on by cattle. They are a trifle costly - $31 Cdn (about $23US) for a wrap that covers a four pack of hives. And you still need a bag of top insulation and plywood sheet on top (1/3 sheet) I am convinced that they handle thebeehive sides just fine. Over time I've concluded that more than just one layer of plastic is required for best results. Even though the hives generally survive with little or no side insulation, they are not as good as those with R5 or so. I guess the real question that I was trying to answer was - how much insulation is *needed* on top? We presently vary from R5 to R25. I'm presently making up top bags and wonder if I am putting more than necessary on top because I am going up to 5 layers of kodel (R5 each). It seems to me that there must be an optimal amount that ensures maximum survival and maximum health in the spring weighed against feed consumption and cost, labour, etc. I've seen hives so hot that they were hanging out in January at minus 10. A friend built an insulated cabinet that held 18 hives in drawers (frames had to be transferred) the whole thing was 8 X 4 X 6 feet and the bees were too hot for the space. He had thought he had the wintering problem solved, but I guess not. It seems to me that if the bees are too warm, they will be too active, if too cold, they will be unable to perform necessary activities and perish or succumb to diseases. To pile on the insulation and then provide a 3/8 by 2 inch hole at the front as many do would seem to be contradictory - but then I do put on a hat and still breathe actively thru my nose (thus losing heat), but find the hat very comforting. I just wonder how thick that hat must be before it is too hot, or the added thickness provides no benefit. Regards Allen W. Allen Dick, Beekeeper VE6CFK RR#1, Swalwell, Alberta Canada T0M 1Y0 Internet:[log in to unmask] Honey. Bees, Art, & Futures <http://www.cuug.ab.ca:8001/~dicka>