Typical HVAC system lasts between 10 and 15 years. However, as your system ages, its efficiency and performance decrease. In this instance, it may be prudent to consider replacing the device after approximately 10 years. No matter whether your HVAC system is experiencing any problems, modern HVAC systems are more energy efficient, which will result in lower energy costs. As well, most of them are covered by a ten-year warranty, so you will not have to worry about having to replace them for quite some time.