I was waken up by my CO detector this morning. I went and got a CO monitor I have from work and it read 35ppm, not too high but 0ppm would be ideal for my house. I turned off the furnace and threw some fans in the windows and it went down to 0 ppm. I turned the furnace on again this morning and placed the monitor right by the vent and it indicated CO but only 4-5 ppm. The furnace is Trane XR80 and is only 7 years old. I thought maybe it could be ventilation problem, but I'm a new home owner and I am just not sure if it is something I could fix quickly or if I should just call a tech.