When I turned my furnace on for the first time this fall, there was an oppressive odor. I thought I would just let it run for a bit and the smell would eventually go away like it had in the past, but eventually, I had to turn the furnace off. The smell was irritating my eyes and throat. I knew I would need professional help, but I was dreading the cost. Since it was still early in the season, the repairman arrived right away. He said he caught a whiff of it as soon as he walked in the door. I did not realize the smell was still there.. The technician went right to my furnace and knew that he needed to clean and vacuum it. I could tell it was really dusty. When the furnace technician asked me when the last time I had my HVAC system professionally cleaned, I admitted that I had not had it serviced at all for five years. Apparently, it should be checked and cleaned twice a year. I guess I was to blame for all dust on my furnace. It was burning dust that I had been choked by when I had tried to crank up the heat. I got my entire HVAC system serviced and cleaned properly and then there was a clean smell when I used it. At least the furnace was still working. I want this system to last a long time so I have resolved do get it the service it needs, regularly..