The life expectancy of an HVAC system depends on several factors, including the quality of the system, the type of system, the amount of use it gets, and how well it has been maintained. On average, a well-maintained HVAC system can last for 15 to 20 years. However, some systems may last longer, while others may need to be replaced sooner. It's a good idea to have your HVAC system inspected and maintained regularly to help extend its life and ensure that it is operating at peak efficiency.