Here's the insulation/ventilation stack set-up I used in addition to my internally-reduced hive boxes.
(from the top of Hive)
Wooden telescoping cover w/ 1.75 inches of foam tucked up inside. (No inner cover used in winter.)
2" tall shim (eke) with two 1" round holes; one each on both the front and back of hive; both holes left wide open all winter (except for bee and mouse proof screening). I started with only one open, but after a week found that wasn't enough, so I popped the plug out of the other and left it open permanently as well.
4.5" recycled comb-honey depth super with stapled-on fabric floor and piled high (into space of shim above) with pine shavings; aka the "Quilt Box".
2" shim with a single 1" hole in the front, that was further reduced during most of the winter with piece of corrugated cardboard as a wind barrier. In the most severely cold period the opening was about 1/2", I made it larger at the end of the winter when it was warming up again; once Spring truly arrived the cardboard evolved in to a flap just tacked to the windward side of the hole as draft barrier - they're still on my hhives at the moment. This is the upper entrance (open for all the colonies during the winter, and for my one strongly top-entrance oriented hive, its main year-round entrance). This shim also functioned as the feeding rim where I placed sugar blocks, and later, patties as well. It also had a 1" hole in back, but I kept it closed with a plastic plug all winter except when I wanted peek in at the bees.
(Various) stack of deeps and mediums containing bees and stores and internally insulated depending on size of colony, etc.
2" shim with NO holes as a wind baffle under the lowest brood box. Similar purpose and effect to a slatted bottom board but w/o the slats which can interfere with mite drop counts. Bees, do not in my (admittedly short) experience draw comb below the bottom of the lower frames. I keep these wind baffle shims on year-round, so it's not just a winter thing. My bees draw and fill and have brood all the way down to the lower edge of the lowest frames.
Screened bottom board with ordinary wooden front entrance reducer that varied in opening size depending on how cold it was; the smallest opening was about 3/4" square; reinforced with mouse guard.
Solid bottom board underneath to contain varroa sticky board; closed at back with wooden piece wrapped in sheet of packing foam to reduce drafts.
My hives sit on Metro-style shelving run from front to back of the hive above a plywood base under the shelving. Plywood is on raised pallets @ 20" above the ground to discourage skunk and porcupine pestering in the late winter.
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The quilt box with its fabric floor, pine filling and two wide open ventilation holes allows the substantial moisture given off by the bees to pass constantly and completely up through and out of the hive stack while moderating the air flow outward and retaining plenty of the bees' warmth below it. Even on bitter days, the temps under the QB in the feeding shim were seldom below 70 F and often @ 90F when the cluster was close underneath. Masses of bees hung out in feeding rim, festooning down in the open space below the QB fabric. I saw no evidence of moisture accumulation or staining within the QB or the hive proper. Some condensation appeared on the lower surface of the insulation under the telecover but it could not fall down on the bees because it was above the shavings in the QB. The bees stayed on the dry side and the condensation vented naturally out through the holes whenever outside temps and relative humidity in the air permitted.
The hives were packed together, side by side, with insulation panels outside and between them. Insulation panels needed between them to take up space required by the overhang and thickness of the telecovers. A 1.25" thick panel is what's needed, but I choose to use 2" because that's what I had on hand. Two hives of perfectly matching heights would probably require 2.75" or 3" to handle the double overhangs. None of my hives was the same height so the packed together better.
I had foam panels on the outside sides, back, and finally when it got really cold on the front, as well. I did not wrap the hives with tar paper or plastic and held the panels on the hives by using ratchet straps. (Which turned into a big PITA whenever I had reason to remove the panels for one reason or another as it is a five-handed job to get them all installed again around such a large blob, even though it was ony three colonies. Am working on a better plan for that this winter.)
I also leaned recycled plastic political signs across the front of the hives (top end ends tucked under the ratchet straps) as temporary wind baffles because I moved my hives late last year (early Dec.) to a new location and misjudged the actual direction of the local winds. This year I will install a better wind barrier in that quarter before frost gets in the ground.
And over all, I had many wool blankets wrapped around the hive, which I think didn't make much of a difference un the end. They did keep the hives warmer underneath and did not (despite being overwrapped loosely with a plastic tarp) trap moisture, but I think it was overkill. I don't plan to do that again this winter but perhaps I'll change my mind. For now, though, it's not part of the plan for 2014-2015.
@NewBeein NH:
You can't insert a quilt box between the two hives as you suggest because: a) the quilt box requires ventilation spacers above and b) the quilt box and its cold-side ventilation mechanism will obviate any warmth benefit rising from the stronger hive to the weaker one above. I think the QB effect really requires a good temperature and humidity differential between outside and in to work correctly. You'd have the difficulties of accessing (for feeding, for instance) the lower box with no practical warmth gain to the upper colony.
In answer to your question: the follower boards were cut from nominal 1" pine boards I had on hand. In practice they are about 3/4" thick. They have "ears" cut on the top edge to park on the frame rests and were very carefully cut to fit closely to the box sides. I even have to plane one or two down a bit to slide them in. Perhaps I was making too much of it, but my goal was to make them into well-fitting interior walls and deny the bees access to the sides of the insulation panels. The (bored during the long winter?) bees decorated them with propolis and wavy wax lines, just as they do the sides of the boxes.
Hope that helps.
Enj.
