Yes, adding an air cleaner to your existing HVAC system can help improve indoor air quality by removing dust, dirt and other airborne particulates. It can also help reduce exposure to mold spores, pollen and pet dander that may be circulating through the air in your home. If you're dealing with an extreme amount of indoor air pollution or have allergies or asthma, adding an air cleaner is highly recommended, as it can provide much needed relief from these symptoms. However, if you don't suffer from serious health issues, then ensuring that your HVAC system's filters are clean and up-to-date should be enough to keep your indoor air quality at acceptable levels.