We went with a Trane system with 2-stage 96% gas furnace, 2-stage 17 SEER air conditioner and variable speed fan. We chose those features mainly to reduce noise and improve comfort. We replaced our old system because it was old and very loud - it still worked fine. The furnace noise came from the 80% furnace's inducer fan and the main blower, and was so loud we had to turn up the family room's TV volume when the furnace was running. We didn't want to wait until existing system broke down and then be under pressure to make quick decision about replacement. We're now retired and home a lot, so we wanted to get a new quieter system now while we can enjoy it. Plus federal tax credit program ends this month. We obtained four bids from contractors with good records on local Angie's List. We rejected the lowest price because the equipment manufacturer had relatively poor showing in Consumer Reports' frequency of repairs report. The natural gas cost savings didn't justify the extra cost for 96% furnace over 80% furnace (15 year payback based on last winter's usage), but we went with 96% anyway because it is totally enclosed ahead making it quieter and it won't draw cold air into the house for combustion, and it is environmentally better. Based on my analysis of gas bills, our annual natural gas usage should drop by 14%, but due to gas company's rate structure, our annual cost will drop by only 7%. Having a more efficient system in place should protect us if gas rates increase. The new outside unit is much taller than expected (45"), due to much larger coil required to achieve high efficiency. My wife had wanted it moved away from under the dining room window, so our original scope was to move it to the other end of the house. With the much larger size unit, we're now really glad we did that. The new system includes some very nice humidity control feaures. The thermostat knows relative humidity based on an outside air temperature sensor. During the heating season, the thermostat controls the humdifier's water solenoid. During the cooling season, the new system will supposedly help remove excess indoor humdity by running the air condtioner longer and slower, which should improve comfort while keeping a higher temperature setpoint. We reused our Aprilaire pleated air filter cabinet (takes #213 filters) which was just one year old. We also reused our Aprilair humidifier which was old but still in good condition. The contractor installed the furnace on isolation pads and also installed fabric connectors between the furnace and the supply and return ducting. With the variable speed fan and the totally enclosed 96% efficiency furnace, the new system is definitely much quieter than before. Installation took 1-3/4 days. Heat was restored by end of first day as promised. All of the contractor's people were clearly committed to satisfying our needs. The contractor provides lifetime warranty on top of equipment manufacturer's warranty, but getting the benefit requires our using the contractor for annual maintenance which will have a continuing cost that we hadn't been paying before. The only shortcoming of the new system is that we'd prefer to have the fan run continuously on slow during the day in the winter, and then have it cycle on/off with heat at night. We can do this manually, but it can't be programmed into the new thermostat. We set our themostat down to 60 at night in the winter, and don't want cold air blowing during that time. During the day we prefer to keep the fan on at slow speed to keep temperatures even and to collect dust.