I am convinced the ductwork is an extreme problem. If you have ductwork then you need to get rid of it. Ductwork is necessary for most cooling systems. Ductwork is horrible though. Most people do not realize how bad ductwork is though. For starters ductwork gets dirty very quickly. Dust and debris gathers in the ductwork easily. Dust and debris is terrible for the ductwork. What the dust in the ductwork does is circulate in the air. If you leave the dust then it is making your air quality poor. The dust is bad for people with allergies and asthma. People are more prone to asthma attacks. Also your allergies are really bad when you leave dust and debris in the system. Your ductwork needs to be cleaned to avoid these issues. The problem though is that it is not easy to clean ductwork. Hiring a HVAC technician is a pretty good idea. A quality HVAC technician could probably clean the ductwork without a problem. A not properly trained HVAC technician will cause more problems though. Ductwork gets leaks easily. When your ductwork gets leaks you lose your air. Air loss is mainly due to leaks in the ductwork. Some HVAC technicians can damage ductwork attempting to clean the ducts. It is a good idea to check into your technician before you hire him. Make sure your professional can handle the ductwork. You do not want your ducts damaged. A good idea would be to look into ductless air conditioning. The obvious reason is the lack of ductwork. No cleaning and no damage. It is an easier system to maintain.