National HVAC replacement costs average $5,000 to $15,000 per system lifespan
https://blogfreely.net/lithilszxt/a-2000-square-foot-home-needs-3-5-to-4-tons-for-ideal-operating-costs
Most residential HVAC systems last 15 to 20 years, but replacement decisions hinge on cost-data benchmarks rather than age alone