HNST Environmental on Instagram: "This was an interesting find. You don’t often see Mold on the exterior of the ductwork in a well ventilated attic. This is caused by condensation when the surface of the ductwork falls below dewpoint. What I believe is happening here is the ductwork is installed too high and airflow between the soffit vents, and the ridge vent is crossing over the top of the ductwork condensing on it. #attic #hvac #ductwork #condensation #ventilation"