JD wrote:

My house was built in '72 (3 br, 2 1/2 bath). The original owner
added a 2 story addition (top part was addition to the master
bedroom). Unfortunately, he didn't put in a new furnace to take care
of the extra sq. footage. When we bought the house in '04, we put in
a new furnace (1 zone) to take care of the 3100 sq. ft. My problem is
that the master bedroom is on the top floor at the end of the house
and furtherest away from the furnace (bottom floor, opposite end). It
is always the hottest or the coldest room in the house. I've got 2
ceiling fans to help with air flow, but it's darn cold in there in the
winter. Oh, and the guy put in 4 skylights in the addition where the
bed is. We've replaced 2 of them due to the fact that he didn't put
the flashing in correctly and the old ones leaked during Gaston in
04. That's when the repair people found the on-going leaking.

My question is: Considering this guy was a DIYer who had wonderful
ideas but his implementation sucked BIG time, what can I do before I
call in the pros and spend big bucks? I have a feeling he didn't wire
things right or that maybe the duct work isn't right.
Hmmm,
What a mess! I never buy a second hand house. Always had my house built
from scratch wherever I lived to avoid such problem. Ideally you should
have 2 zone system and it'll cost $$$ to do it right the first time.
Is the addition properly built? I mean building permit was taken out for
the work and official building inspection done properly? Is it of sound
structure?