I'm thinking about getting a new furnace and have met with two dealers. The driving force is the fact that I want to get central air. Since the furnace is 35 years old, I thought it made sense to replace it at the same time. The first guy was a Carrier dealer and after reviewing the situation, he said he wasn't sure replacing the furnace was the best thing to do. My house is about 1300sf. My gas budget is $90. He recommended tuning and cleaning the furnace at which time they would inspect the heat exchanger. It guess the current furnace should be 65% -70%? efficient and he felt I should consider the payback time on the investment. That kind of shocked me. My concern was what happens if it fails in the middle of January. He indicated a new furnace can be aquired and installed in 8 hours if it came to that. His position was this furnace could last a number of years yet. He would be happy to sell me a new one if that is what I want and is preparing various estimates. Dealer two is a Lennox dealer which is what I have now. He soon implies I'll want a high efficiency furnace and recommends a Goodman or Amana which he says are just as good as Lennox but cheaper. I ask about 80% furnaces and says he doesn't recommend them anymore but will quote them if I want. He provided various systemquotes. Also both seem to think a 10 seer air unit would be a decent option and told me you won't be able to get them after January. They also provided 13 seer options. Both seem to have good reputations. Opinions?