Heat retention is such an integral topic to Warre beekeeping that I thought it deserved its own post.  The entire hive is designed around the idea of making the inside easy for the bees to keep warm while preventing too much heat loss (or gain in extremely hot areas) from the outside.

The extra boxes at the top of the Warre hive are meant to prevent condensation inside the hive while still keeping the interior warm.  The part I'm the least clear on is the vent under the eaves of the roof --- it doesn't connect to the rest of the hive, and I think its purpose is to move hot air away from the top of the hive when the sun is pounding down in the summer.

Below the roof comes the "quilt" layer, which is actually a wooden box with burlap attached to the bottom so it can hold straw, wood shavings, or leaves.  The organic matter acts as insulation and also soaks up moisture, preventing the problem of condensed cold water dripping on the bees in the winter.  The beekeeper changes out the insulation layer every year, or more often if it feels damp.

Next down comes another piece of cloth that takes the place of the inner cover of the Langstroth hive.  The cloth is somewhat permeable to moisture-laden air, so it allows damp to move upward into the quilt where it won't bother the bees.  The cloth can also be pried back partially to peek inside the colony, a process that doesn't tend to jar the hive as much as removing a wooden inner cover would.

The Warre hive body itself is considerably smaller than boxes in Langstroth hive, again for the purpose of heat retention.  The winter cluster fills more of a Warre box than a Langstroth box, which makes it easier for the bees to stay warm.  Meanwhile, their honey stores are above the cluster rather than to either side of them, so the bees can travel up to eat (which is easier than sideways, around frames).

Speaking of frames, even the top bar setup is part of the heat retention design.  Warre believed that frames make it harder for bees to heat the hive because air flows up the gap between the frame and the walls.  Without frames, the bees build their comb all the way to the sides of the boxes, creating a more solid barrier to air movement.

David Heaf's final observation on the topic is that mesh floors are problematic because they increase consumption of honey by 20% in the winter without (he believes) cutting down on varroa numbers.  Although some beekeepers put a solid drawer under the mesh in the winter, that just makes a spot for debris and microorganisms to accumulate where bees can't reach and sanitize the hive.

The reason I'm spending a whole post on talking about the heat-retentive design of the Warre hive is because I think it would be possible to take a hybrid approach without embracing the entirety of the Warre method.  If you were afraid of nadiring and really wanted to be able to check on your bees at intervals, you still might get better results by changing over to a Warre hive structure without using the entire set of management techniques.  Or you might simply add a Warre-type roof, quilt, and cloth assemblage to the top of a Langstroth hive and see what happens.  I figure our eventual beekeeping system will probably be a mish-mash of bits and pieces we like from many different beekeepers' philosophies, so it's worth understanding how and why certain methods work.