Hi. We live in Western Pennsylvania and are considering replacing a 30-35 year old furnace. So far we have one estimate and it is for a one stage Trane 92% efficiency. We have a small 3 bedroom ranch home with 11 windows counting one in the garage and one in the basement. The attic is being insulated with R-38 batts and that will bring the total insulation to around 15 inches or so. The basement measures 35'6 X 23' 3". There is one cold return and one heat register in all of the rooms except the living room which has one cold and two heat. The contractor did the J-1 calculation.
After the contractor left I went to the Trane website and used their calculator to recommend a furnace for the house. The calculator recommended a two stage unit. Obviously, I need to ask the contractor why he did not recommend a two stage unit. Do you people recommend a two-stage furnace based on the above information? Any helpful hints on guiding us in the right direction? Is it true a two stage unit can make a house feel cold? Thanks to anyone who responds.