If your commercial HVAC system has been giving you problems, it's time to talk to an HVAC contractor. Commercial HVAC systems are designed to last up to about 20 years, with the proper maintenance. However, once they reach their limit, they do need to be replaced. Unfortunately, if you don't replace your commercial HVAC system in time, you could be left with problems you weren't expecting. Luckily, the list provided below can help you avoid that.