Safety first:Suspect natural gas, smoke, fire or an active CO alarm? Leave the area and follow local emergency guidance before troubleshooting. Gas / rotten eggsSmoke / burning
HVAC & vents

HVAC & vents odor troubleshooting

Musty, sour, burning and sewer-like odors that appear when air starts moving. These are focused diagnostic guides, not an exhaustive list of every possible defect or local code condition.