The core idea
Condensation risk depends on whether a surface is cold enough for the surrounding air, not on relative humidity alone.
How the mechanism works
Air reaching a surface below its dew-point temperature releases liquid water onto that surface.
When it becomes relevant
Typical trigger: Cold weather, cooling operation, night-time glass cooling or high indoor moisture generation.
Evidence that supports this interpretation
- Surface temperature approaches or falls below dew point
- Water forms first at the coldest edge
- Lower humidity or warmer surface reduces the symptom
Evidence that weakens it
- Water appears during rain regardless of temperature
- The moisture is between glazing panes
- A plumbing event reproduces it
What this concept cannot prove alone
A single observation, image or meter reading cannot confirm the complete failure pathway. Use this concept to form better questions, compare alternatives and decide which safe observation would be most informative next.
Safety and professional boundary
Consumer measurements are screening evidence; persistent concealed condensation needs building-envelope assessment.
Primary references for this topic family
These references ground the general building-science or safety context. They do not diagnose a specific house, replace local requirements or certify a repair.
