Our furnace salesman was excellent...and that's about all that blew us away. The contract stated that they would not smoke or swear on our property...and they did both. They missed the fact that there would be a giant hole when they pulled the old furnace (you would think this was the first time they had done a replacement in a home from the 70's). After the installation it sounded like there was a jet engine in our basement that I was told was normal (it turns out that a cold air return was completely closed off and two different people couldn't figure this out?) They missed that there were two ducts that were knocked off during the installation. They didn't insulate my cold-air return so in Calgary...in minus 30 weather, my cold-air intake became covered in three inches of ice that melted and dripped constantly onto my $3000 washer-dryer pair.
The explanation for all of the incompetence? A since fired furnace installer...Well that's great but how are you going to fix this? They sent a new guy to leave chunks of insulation all over my house and two ducts were still left un-hinged...Let's just say I gave up and waited for my father-in-law to come for a visit!