As a homeowner, you want to make sure that your HVAC system is running smoothly and efficiently. But how often should you replace your HVAC system, and when is it time for an upgrade? The answer, of course, is that it depends. In this series, we'll explore some of the factors that you should consider when making the decision to replace or upgrade your HVAC system. We'll also share expert reviews on the top HVAC system repair and upgrade companies and contractors, prepared with the busy homeowner in mind with our experts.