I just moved in a house that has a furnace in the attic. Within a week, I I was getting headaches constantly and two of my dogs were sick; simulatenously I smelled gas and called the gas company and lo and behold the furnace hadn't been serviced/cleaned in years and the burners were misfiring.

Went a few days without heat, the tech came said the burners were clogged and cleaned them out. Then I told him I still smelled gas down near the main gas line which runs by the hot water heater and big surprise, one of the valves was markedly loose and leaking. He tightened the valve with a wrench and that was it.

A week later, I still smell gas on and off but can't find the source. One morning, out of the blue, the carbon monoxide detectors start going off. I called the contractor back and no one answered. So I called the gas company and they dispatched the fire department. The fire dept didn't find a specific source but strongly recommeneded someone look into a backdraft situation and possible ventilation issues as they were cautiously concerned when looking in the utility closet at the H20 heater and furnace in attic.

Then, the gas smell starts getting worse. I could only really smell it after the furnace had been on and it was when you opened the utility closet with access to the attic (where the furnace is) and the Hot water heater, and from the vents which are all in the ceiling. Then, my friend one day started smelling it too.

So last night, the owner's contractor came out again and tells me nothing is wrong. I asked specifically about a backdraft and he acted a little perturbed and all of sudden the exhaust for the furnace and H20 heater is too small - 4in and needs to be 5in. (why this wasn't caught the first time, I don't know?) Then he proceeds to say that the house is safe, there is no real issue and he is a contractor of the owner not me and basically accuses me of sabotaging the place and trying to blow it up for insurance money (I'm totally not joking, this actually happened). Then he procceeds to tell me that natural gas, even when it leaks doesn't make you sick and for carbon monoxide to make you sick, it would have to be enough to kill you (which I know is false and called his bluff). So I'm not actually getting sick and throwing up at home, it's all in my head.

So, I'm not really sure where to go with this. It's my understanding that backdrafts aren't safe and I'm also not sure that anyone has ever checked the duct work. This guy never really checked the ventilation or got in the roof either. I'm really borderline scared to be in this place at the moment. I have no heat because the earliest this will be fixed is a few days and I'm also not confident that this is 100% the issue.

Is there something else I should look for or look into?