Arcon AC sold me my air conditioning unit and a couple of years later, I developed some kind of mold in the air duct system. So I called the manager and he came out and looked at it. He told me I could either clean or replace the ducts. After I did either one, he also recommended I get an ionizer to spray all around the house to get rid of the spores. I did what he recommended and the air is cleaner, it smells better, and I'm very satisfied.