Do I need a new furnace, or I am being sold the wrong thing?

[DK]

That variance is normal. Some people like the themostat set on 80 and some 68. Some turn it down when they leave and some don't.

[trader4]

messagenews: [e-mail]...

to fix it,

It's not unusual to have the gas company red tag a furnace that has a backdraft problem, as it's considered a serious safety issue and they would rather be safe than sorry. One time the gas company replaced my meter and then came in to relight the pilots. It was a very hot day in summer and the water heater is in the basement. They checked the WH for backdraft, and it failed. They red tagged it on the spot.

Then why are you surprised that the gas company gave him ONLY 5 days to fix it?

Usually they check for backdraft by holding a match or other smoke source near the diverter vent. If the smoke blowss away from the vent, it fails.

That may just mean the chimney is

Yes, and that's why the gas company says it should be fixed now.

Get a CO monitor before you go to

That's a very good idea. I have a CO monitor in the bedroom and another one in the basement.