yaofeng wrote:
We are finally replacing the HVAC in our house. The furnace is
original in 1971, 140,000 BTU. Central air is 3 1/2 ton Trane put in
1987. The new ones will be both Trane units. The new furnace will be
92.5% AFUE 112,000 BTU. AC is the same tonnage at 15 SEER.

Did the contractor do a heat loss / heat gain calculation to come up
with those sizes?