Some detectors are more sensitive than others. If no one has CO symptoms, the above procedure, including having the home checked by a qualified professional, can be used. Find out what caused the alarm. Contact your heating contractor for help in tracking down the CO source. Do not assume, that because you can't see, taste, or smell anything, there is no problem.
Carbon monoxide has no color, taste, or odor.
Find the CO source. Determine why the CO remained in the house rather than vent to the outdoors. Episodes of CO can be sporadic and hard to detect. Once doors and windows are opened, the CO source is difficult to determine. If your detector alarmed there is a reason.