Neglecting the 20 Percent Rule Exposes Your HVAC System to Premature Failure

https://sacramento-precision-hvac-affordable-sac-sac-ca5294.zenbloomer.com/posts/continuing-repairs-on-18-year-old-hvac-units-traps-you-in-escalating-failure-liability

The 20 percent rule for HVAC states that if your system costs 20 percent or more of a new unit to repair, you face a premature-failure liability that makes replacement the smarter choice