A faulty gas heater can cause serious problems. Health problems that seem to be worse, or only occur when the heating is on, may be caused by carbon monoxide from a faulty gas heater. Symptoms of carbon monoxide poisoning include:
Shortness of breath
High levels of carbon monoxide are very dangerous and may cause people to pass out or even die. If you suspect you may be affected by carbon monoxide, open windows and doors, turn off the appliance and go outside to fresh air. See your doctor and ask whether your symptoms may be related to carbon monoxide.