I have to run that much vent pipe because I have no wall to exit
through and as I said, I have to run the pipe to a suitable exit
location. I think I would save enough money on vent pipe to pay the
difference in the 93% furnace. I'm not too worried about freezing as I
will keep the garage heated to above freezing. If installed properly,
wouldn't all the condensate drain? That's what I'm curious about, I'm
not to sure how these are built and how the condensate drains. Thanks
again.
Steve

It depends on the brand. For example, most Carrier (& Bryant, Payne,
etc) have internal traps that could be damaged by freezing. Goodman,
for example, has an external "cup" that the condensate drains into but
that could freeze also, not damaging the unit but it would still need
to be thawed before the furnace could drain properly. Most furnaces
would need heat tape around the trap and possibly also around some
internal plumbing to keep the condensate from freezing and clogging or
damaging the furnace.

You would keep the garage heated above freezing all winter??

Feel free to email me off list if you want to kick this around some
more.

JK