I was really excited to have Mack out to quote a replacement furnace/AC, based on everyone's…read morecomments on Reddit, Nextdoor, and elsewhere. I really wanted someone local, independent, and that I could call and they'd answer -- and be honest. But... I was incredibly underwhelmed.
I was after a full replacement system, with a slight preference toward replacing the AC unit with a heat pump. I also wanted a two-stage system due to slight temperature imbalances in the house. He very quickly dismissed heat pumps, saying that they're "worthless" in Wisconsin, and he also didn't entertain the idea of a two-stage system.
I asked about going from a 1-inch filter to 4-inch, and he said, "No, I wouldn't do that. The thicker filters restrict airflow too much; I would just get a higher quality filter." This is just blatantly incorrect and the exact opposite is true. 1-inch filters with higher MERV ratings are what restrict airflow.
I also had a 45,000 BTU furnace, which had had no problem heating our home (and it was 20 years old! -- both the unit and house), but he very quickly said, "Oh, that's too small. You should get an 80,000," without taking any sort of measurements, asking any questions, or looking at the rest of the house. You can't do a load calculation based on...nothing? And you can't just nearly double furnace capacity without causing issues (mainly, that it's going to short cycle from being oversized). And, as mentioned earlier, it wasn't going to be a two-stage furnace, so it would have run at that full 80,000...
Maybe he's good at repairs (I don't know), and maybe he's well priced (he came in second cheapest out of the four bids I got), but these were all just fairly big red flags for me that he wasn't a match for me for doing a new install. I got a two-stage heat pump and two-stage furnace setup from elsewhere and so far am very happy!