What is the lifespan of a Lennox AC unit?

What is the lifespan of a Lennox AC unit is 15 to 20 years with normal residential use and proper maintenance, which is similar to industry average for AC units of 15 to 20 years and similar to Trane and Carrier. Lennox AC units including ML14XC1 14 SEER single stage, EL16XC1 17 SEER two-stage, XC20 20 SEER variable speed, and XC25 26 SEER most efficient are built with heavy-duty coils and compressors. Life depends heavily on climate, usage, and maintenance. In hot climate like Texas and Florida where AC runs 8 to 10 months per year, life is 12 to 15 years due to more run hours, while in moderate climate where runs 4 to 6 months, life is 16 to 20 years. Factors that shorten life include lack of annual maintenance with coil cleaning, dirty filter causing high head pressure, and poor installation with incorrect refrigerant charge. Lennox units use proprietary parts that can be more expensive than standard parts, but service rates around 9 to 12 percent are decent. Common parts that fail first include capacitor after 5 years at 150 to 300 dollars, contactor after 7 years at 150 to 250 dollars, and compressor after 12 to 15 years at 1,500 to 2,500 dollars. Lennox offers 10-year parts warranty when registered. To maximize life, change filter every 2 to 3 months, clean outdoor coil with hose monthly, and schedule annual tune-up for 100 to 150 dollars.