While it could be problematic for a stove blowing out, it's slightly worse. If in your home, the most readily available airflow is through the exhaust vent of

While it could be problematic for a stove blowing out, it's slightly worse. If in your home, the most readily available airflow is through the exhaust vent of your gas water heater or HVAC unit and either are running it's possible for the whole house fan to pull the exhaust (carbon monoxide) into the house. This is why it's very important to consider where a whole house fan is placed as well as ensuring there's enough incoming air through an open window or vent. Ours will do this if we don't open a window. For an abundance of caution, I have a CO detector in the HVAC closet as well as one's elsewhere in the house.