dryer

Warm yes, hot no.
Cleaned it out lately?
Kinked up hose?
Cheap plastic or foil hose?
What's on the outside? Are the louvers or flapper stuck with lint?

Fiol hose from the dryer to about 4 feet up to the ceiling, then wood stove pipe going into ceiling panel and out to exhaust .
Flaps are clear.
Not really hot , hot. I can hold it without burning , so I guess "warm"

Get rid of the foil hose, and use Sheet metal 4" all the way, with a elbow to attach to the dryer. Tape the joints, do not use screws, since they can catch lint. As for the vent, that is one of the biggest heat loss culprits in the home. Change out to either a Mushroom style vent, or one with a single flapper that will close to seal the opening, to keep outside from coming back in.