Bert Hyman writes:
Do they work (the temperature compensating part, that is)?

They seem to. We've got a new Bryant system -- Bryant
furnace, humidifier, and thermostat. We installed a
standalone outdoor temperature sensor (if we had an AC unit,
the compressor would have one built in, but we don't), after
which the thermostat let us turn on automatic humidity
adjustment. Now we can set a baseline humidity, which the
thermostat then adjusts downward with the outdoor temperature.

The trick, then, is finding the right baseline, so that you've
got comfortable enough humidity during the day without
allowing condensation to form at night. That's pretty easy --
you just start the humidity setting high and then decrease it
gradually until you stop getting condensation on the windows
at night.

Most of our windows are double-paned and also have storm
windows. Even with the humidity baseline set as high as it
will go and the temperature outside below zero, we don't get
any condensation on those windows. Furthermore, since we
recently blew insulation into our exterior walls, we're
probably not getting much condensation in them either.
However, we've got one old decorative stained-glass window by
the front door, and we do get condensation there, so we've had
to turn down the baseline a bit. I suppose we should install
a custom-fit storm window on the stained-glass window or
something.

As we've turned down the baseline humidity on our thermostat,
the decrease in condensation on the stained-glass window has
been obvious, but the house hasn't been uncomfortably dry, so
it seems clear that the temperature compensation is working.

(Granted, we're in Boston -- I escaped from MPLS 26 years ago
-- and it's entirely possible that they might not work as well
at the kinds of temperatures y'all get there in the frigid
midwest.)