I live in Washington State and would like to know if anyone has an idea of what a reasonable price would be for a replacement of my heating and cooling system. Our house is a 2 story with roughly 2,500 sf. I am considering a new Trane system 3.5 tons XL15i HP, replacing the auxiliary heat system in the garage and new thermostat.

Beyond that I believe the installation should be pretty straight forward. At this point I'm just trying to understand if I am looking at $6K-$9K, $13K-$15K or something in between. Any reasonable guidance would be greatly appreciated.