I assume this is condensation, but is it something I can fix myself? It is only happening on one vent as far as I can tell. It is on the ceiling (by far the most difficult vent to reach in my house!)
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can you get into the attic above it? If so go look from that side.Counterpoint said:
Dang. I wonder which is cheaper, buying a much taller ladder so I can safely reach it or just calling an AC guy?