Load calculations sound real nice, and make a good impression. In reality,
the new equipment (and it's air flow) must match your existing duct work.
BTW, In my state there's a 3 day "cooling off period" in which consumers can
change their mind. This can be waived by the consumer in an emergency.

"pipco" wrote in message
ps.com...
Thanks. I'm planning on getting a 90% efficient furnace. My real
question was about 2-stage and variable speed furnaces. Although the
more I read about it, I don't think the varaible speed furnace is the
silver bullet to my problems, especially with the age of my house and
less-than-perfect insulation/windows. I'll probably just go with a
standard 90%.

No one has done a load calc yet. They all say that before installing
they will do a load-calc to ensure the correct size, although everyone
has suggested 80,000 btu.