I thought I'd share this with anyone interested. I just found
out that the new LED recessed lights solve serious problems that
exist with recessed lights, depending on where they are installed.
Case in point, I have 9 of them in a cathedral ceiling. With
conventional lights, that isn't good. First, the area around
the lights typically has no insulation, so there is heat loss.
Second, with a metal fixture, it gets cold, transferring the cold
to the trim. That causes condensation in the winter. I have
paint peeling around the lights. In the past, I've repainted
and it's OK for a few years, but then returns. Besides the heat
loss due to no insulation, there is also significant air leakage
because most of these are not even close to being air tight.

So, I just discovered that LED retrofit kits exist that solve
all this. They come in 4, 5, 6 inch versions and consist of
an adaptor on a length of wire that screws into the existing
socket. Then the new LED light gets pressed into the existing
fixture. It solves the above problems. They are available in
depths under 4", so there is still space for 3 or 4 inches of
insulation above it. Second, they are inherently mostly airtight.
Some pass an ASTM standard that says they are in fact airtight.
But even the ones that don't say they meet the std, sure look
airtight to me, especially if you put a little caulk under the
trim before shoving it in. They are almost all made of plastic
too, so transfer of cold will be limited.

They generally run about $35, but there are ones that cost more
than 2X that. Lowes has a Utilitech one that is 5 or 6", 700 lumens,
equiv to about a 65W, for $25. So, if you have recessed lights
in a cathedral ceiling or going into an attic space, they are
definitely worth considering.