This system is great for people in the northern United State who don't need cooling all day during the warm months. At 13 SEER these systems can only be used in northern states and will cool your home using standard compressor technology and heat your home using natural gas (convertible to propane with additional kit).
These systems are solidly economy class and are designed to put up-front costs ahead of long-term costs of operation or comfort. Many of these systems will use the same furnace technology as has been available for 30+ years.
This AC and furnace system begins with the Goodman GSX130241 which is a 13 SEER Air Conditioner, and is paired with your choice of the following selectable Goodman Furnaces (prices vary): GC9S800403AN, GC9S800603AN, GC9S960403BN, GC9S960603BN, GC9C800603AN, GC9C960403BN, GC9C960603BN, GC9C960803BN