Direct answer
Document the first location, trigger, date, operating state and one unaffected comparison before cleaning or changing anything. That preserves the evidence needed to test Wind, stack effect and seasonal reversals later.
Why this question matters for Wind, stack effect and seasonal reversals
How outdoor temperature and wind direction shift pressure across floors and façades. In the wider path, the observed clue is stale air, drafts, door movement, uneven temperature or odor transport A good answer stays tied to the actual sequence instead of converting a familiar pattern into a diagnosis.
What to compare
Include bedroom, closed room, stairwell, mechanical zone, return-air path or exterior boundary, nearby systems, recent work and the places where the symptom is absent. The main lookalikes remain insufficient outdoor air, duct imbalance, envelope leakage, blocked transfer path and room-specific heat gain or loss.
A useful evidence record
Write down the exact location, date and time, weather, equipment or water-use state, recent changes and one unaffected reference. Preserve photos before wiping, opening, repainting, tightening or resetting anything. State uncertainty directly.
How the answer changes the next step
If the result strengthens one pathway and weakens another, continue to the matching safe-check or scope guide. If both explanations remain plausible, repeat under controlled conditions or prepare a professional handoff rather than choosing a repair by guesswork.
Safety boundary
Combustion backdraft concerns, carbon monoxide alarms, strong fuel odor or unsafe electrical equipment require immediate safety action rather than airflow experiments. HouseSymptoms provides information and documentation structure; it does not certify a diagnosis or authorize regulated work.
