We can't get rid of the burnt hair smell

That is how terrible I dislike the burnt hair smell, but he showed me all the gross debris he got out of our HVAC ducts.

My heating equipment smells prefer burnt hair anytime I turn it on. I am driving myself deranged trying to eliminate the burnt hair smell. First, I tackled the furnace filter. I cleaned the filter and tried it again. That did not work so I bought a whole new one. I then took our furnace totally apart and cleaned the inner toilings. I dusted, vacuumed and wiped anything I could find. I removed huge chunks of hair and dust from the heater. You would think that would do the trick, however nope, the heating technology still reeks when it turns on. I thought I had a brain blast the other day. I called our HVAC supplier for ductwork cleaning. They say every 5-7 years the air ducts need professional cleaning. I could not remember the last time so I figured that is where the hair must be. I had the HVAC company particularly disinfect every little bit of ductwork. I even paid him extra to take his time with it. That is how terrible I dislike the burnt hair smell, but he showed me all the gross debris he got out of our HVAC ducts. I was excited thinking our issues are all solved, and well I just ran our oil furnace equipment and it still reeks. The smell is a little better, but I can still smell burnt hair. Is the hair deeper in our oil furnace than I thought? I am thinking that maybe I need a professional to take apart the heater. I might even buy an air cleaner I dislike the smell so bad.

a/c installation