I had written a while back that I had really bad window condensation
issues in my fairly new house; so bad in fact that it was freezing
moisture on the seals on the inside of the wood. Not good.

I had talked to more than a few HVAC people in the area. (What is it
about HVAV people that negates their ability to actually return phone
calls even after visits and even when awaiting quotes?) I finally talked
to a nice local place that sent a guy out for nothing; a "consult". He
made two interesting observations that finally laid claim to what may
have been most of my problem.

First, my blower fan is a 3 speed fixed. The AC was wired for High, and
the heat was wired for Low. Even with all the vents wide open upstairs,
there wasn't jack making it up there. He hinted that I might swap those,
or try Heat on Medium instead of Low.

Second, he noticed (How did I ever miss this?) that the idiots who put
the system in actually ran a vent from the third floor into the cold air
return. The room in which this vent resides has a cold air return on the
opposite wall. Needless to say, that's going to cause a misbalance.

I tried swapping AC for Heat on High, but that just managed to heat less
air due to it's speed. Not surprising. So I bumped it down to Medium. I
also shut off the misrouted vent.

So for the last month, BOTH floors have been within a degree of each
other. That's NEVER happened before. On top of that, I've yet to have
any more condensation on the windows. Granted, we've had fewer cold
days, but we've still had some low 20's, mid'teens days. I used to have
condensation even at the low 30s mark. I'll assume this heating
correction has put the house in a positive pressure state now that we're
actually getting air flow up there.

Go figure. It's nice to finally not be stressing over the wood windows
rotting out before my eyes. And the solution was cheap enough. :-) On
top of that, the electric bill didn't increase at all with the blower
change, so I'm assuming it's running even less that it used to.

-=Chris