Troubleshooting center
Humidity & Condensation
Clammy houses, sweating ducts and registers, musty smells — and what drives them.
Each guide answers the question first, then explains the likely causes in order — duct leakage only where the evidence actually supports it, and a licensed HVAC contractor where it doesn’t.
5 guides in this category
House Humid With AC Running
Cooling and dehumidifying are not the same job, and a system can do one without the other.
Read the answerDucts Sweating in the Attic
Condensation on ductwork means a cold surface is meeting warm, humid air — usually an insulation or leakage issue.
Read the answerCondensation Around Vents
Sweating registers usually mean warm, humid room air is meeting a surface cooled well below the room's dew point.
Read the answerCeiling Vent Sweating
A sweating ceiling register risks staining or water damage and usually traces back to insulation, a boot gap, or nearby duct leakage.
Read the answerMusty Smell From Vents
A musty odour from vents usually points to moisture somewhere in the system and is worth having assessed rather than masked.
Read the answer
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