Bill Morong says "What I wish to learn is how to optimize letting
out the bad stuff without letting out more heat as heated air than
necessary.  Heat is wear on my bees, and honey."

My understanding is that "the bad stuff" is the condensation that forms as
the heat rises and meets the cold surface of the outer cover, the top of the
straw, shavings, or whatever, etc.  I am not aware that anyone has ever
demonstrated that carbon dioxide or any other by-products of respiration
accumulate to harmful levels.  (Feces, of course, can lead to real problems
but normally healthy bees can apparently cope with what little there are.
Dysentery is another subject...and not being discussed at the moment.)

The straw, shavings, fiberboard, etc. all act to capture the moisture and
prevent it from dripping down on the bees and chilling them.

I have always understood that good top ventilation is in lieu of straw,
shavings, fiberboard, etc., but am aware that some beekeepers do both. (Just
as some of us wear both a belt and suspenders.)  The top ventilation lets
the heat escape before it hits the cold surface of the cover and causes
condensation.  My understanding is that recent studies have shown that the
bees do not heat the hive, but only themselves.  Further, they are so stingy
with this heat that the bees on the outside of the cluster are just about in
a stupor because they are so cold.  I recall that temperature probes have
found the heat down to the 50's on the outside layer.

I have thought this means that it is impractical to reduce the heat produced
by the bees, and our management should be concentrated on dispersing that
heat without causing condensation.

Lloyd
Lloyd Spear, Owner, Ross Rounds, Inc.  The finest in comb honey production.
www.rossrounds.com