I noticed that our exposed sheet metal basement dryer duct gets quite cold here in the frigid North -- acting like a "reverse" radiator when the dryer is not in use.
Part of the problem may be due to the fact that their is no louver on the exterior penetration (it goes through a window pane that has been replaced with a sheet metal panel with integrated, un-louvered hood).
So, 2 questions:
- Should the dryer duct be insulated and if so with what product?
- Would replacing the penetration with something louvered be likely to make a significant difference (and be advisable)?
Interestingly, the intake/exhaust pipes on our high efficiency furnaces don't seem to "radiate" as much cold despite also being unlouvered -- probably because they are PVC rather than metal and also smaller diameter.