Our house had a '68 Chrysler Air Temp, and I ok with having it for a few winter and update as needed..
The first few weeks, of having it, wasn't happy with it.. It was way oversized for the house.. So, this is what we had.. turn it on, and took some time for it to heat up and run the blower.. Once it was going, blast of heat out of the vents, and really could feel the cloud of heat coming down to the family room downstairs!!! Our bedroom is at the end above the garage, and it was cold. As it was oversized, it ran a short cycle. The gaas budget bill was $120 a month.
The fan motor was getting pretty loud, and gave out. Re called the dealer in and get a bid, and house called for 60k BTU furnace. We installed a two stage Trane XV90, and what a HUGE change in comfort in the house.. The furnace runs 1st stage most of the time, and temps in the house is much more even, and longer run time now lets the bedrooms get warmer. Our gas budget plan dropped down to $70 a month.