Wrap everything including any pliable sections near the dryer and secure it with the tape.
Insulated dryer duct in attic.
Ensuring your attic is properly insulated is essential to this endeavor.
When these ducts are exposed to exterior air the plastic jacket never gets cold enough to permit condensation because the hot attic air keeps the plastic jacket warm.
How to insulate your attic duct system step by step with video instructions as winter nears many will begin to activate their home heating system to keep the house warm in the blustery and frigid temperatures that accompany the change in seasons.
Table 1 shows effective r values for 8 inch round ducts at three attic insulation levels and three duct insulation levels r 4 2 r 6 and r 8.
Insulation that s carefully wrapped around the duct will work better than fiberglass batts just piled on top.
Attach the insulation with a high quality reinforced foil duct tape.
The more insulation you install the less likely you are to have condensation in the ductwork.
Standard duct tape can heat up and fail over time so get the good stuff.
Do not use sheet metal screws to connect the ductwork because the screw tips protrude into the duct and will collect lint.
The international residential code allows you to run a dryer vent through the attic but you can t terminate it there.
Doing so would fill your attic with warm moist air that could rot the framing.
Finally caulk around the opening where the pipe vents to the outside to prevent any cool air from sneaking in.
Most attic ducts are insulated flex ducts that is flex ducts with r 6 or r 8 fiberglass insulation along with an exterior polyethylene jacket.