Carbon monoxide poisoning

I use gas for hot water and heating in my house.
my dad often worries about carbon monoxide poisoning, cause I live alone.
so I wanted to know:
what are the symptoms of poisoning?
does it take a long time to get ill/die?
cause I heard you pass out.

One symptom is bad headaches. Another is death - after you pass out.

Simple solution is to get a CO2 detector/alarm. It looks just like a smoke detector, but it is for CO2.
Also pay to have a professional come out and clean your heating system. Change your furnace filters regularly.
Hope this helps. Good Luck!!

I properly installed and maintained gas furnace or water heater will not put you in danger of carbon monoxide poisoning. For peace of mind you can have your water heater inspected and carbon monoxide detectors are available that will alarm if dangerous levels of CO are detected.

Symptoms of CO poisoning include headaches, nausea, flu-like symptoms, lethargy, fatigue, convlusions and death depending on level and duration of exposure.

bimjob, I think you mean CO not CO2. CO2 while a greenhouse gas is not toxic and isn't dangerous until it is concentrated enough to displace most of the oxygen. CO is deady in concentrations under 1%