I have two Natural Gas fired furnaces, each with a central Air Unit with compressor outside. They are both down flow with the heating ducts under the slab and the return air through the attic. One is 125k btu furnace in the garage utility closet with a 3.6 ton air and the other is a 75,000 btu in an inside hall closet with 2.5 central air unit with compressor outside. They are 25 years old and one is giving some problems. It may have a cracked heat exchanger and or a defective thermocouple. There is some yellow tips on the flame and the pilot light is frequently goes out. I would like to replace these units myself. I live in Oklahoma where ac is more important than heating, although it gets moderately cold here in the winter.
I would like to buy a couple of higher efficiency units that would not require extensive plennum work versus the ones that I have now. In 1971 I installed a 2 ton central air in my first little house. The lines, condensing unit and evaporator were precharged and it was a fairly easy installation into an existing forced air furnace in my basement.
Do you know if I can still get this kind of kit and is it still legal to install my own heating and cooling system? What is a good and available brand and an economical source for it?