A smell from an air vent does not identify mold, bacteria, a dead animal, or a duct problem. Musty, burning, sour, and rotten-egg odors can have different sources and may require different responses.
Respond safely and investigate the source
If you smell gas or suspect a leak, leave the home immediately. Do not operate lights, switches, electronics, or a phone inside; call 911 or the gas utility from a safe location. If there is smoke or fire, leave and contact emergency services.
For a non-emergency odor, check the filter and arrange an HVAC assessment. EPA says routine duct cleaning has not been shown to prevent health problems. A musty odor alone does not establish mold; ask for suspected growth to be documented.
Local next steps
If you are in Little Creek or elsewhere in Virginia Beach, a photo inspection can document an accessible duct concern before you choose service. For a separate pest-entry problem, see Universal Pest in Virginia Beach. Compare the tier-specific benefits of the Total Home Health plans.