They sent a tech over it was about 30f. He took one panel off and said the heat exchanger was probably cracked. Said it didn't matter to continue they probably cannot get parts for it. Went into the house took a carbon monoxide reading it was 1 ppm. Despite 1-9 ppm is acceptable to BPI and American Society Of Heating, Refrigeration And AC Eng. Standard 62.2. He disconnected the unit (left us without heat) would send us info on a replacement and left plus billed us 1.5 hrs. A second company came and took it apart, the heat exchanger was fine and it needed only a cleaning and no CO detected. They said the GM would call us, never did. Will file a complaint with the BBB next.