They came on Friday to check on the problem (compressor fan was dead and we needed obsolete freon). Our unit was 27 years old, so we replaced the whole unit. They came back the next Monday and completed a full install and showed us how to use the thermostat. Everything was great (they put a dropcloth down and cleaned up) and I feel like the price was reasonable. For a roughly 1,700 sq. ft. 2-floor house, it cost just under $16,000 to remove the old unit, replace the intake duct and extend some other ducts, and install an entire new Carrier unit with thermostat. I didn't shop around because this company has an excellent reputation. Just posting the cost for those who might want to shop.