Does heat transfer through an air-tight seal?

heat is form of energy transfer which is subject to entropy, there is no place in the universe where heat (or energy) can be preserved without external source. even sun die, so are galaxies and finally will our universe dissipate to lowest possible energy level where even atoms will collapse.

space would sap the heat completely. If you sealed the hot object in something that doesn't transfer heat at all, and kept the cold object on the other side of said seal, then the heat wouldn't transfer. That's not to say the hot object would stay hot, but the cold object would stay cold.

Heat is the movement of atoms, eventually the atoms would settle down and reach an equilibrium with the surrounding area, which would be cooler than when it was heated up.

Heat as an energy will pass from one thing to another in all cases. The rate of tranfer can go fast or slow depending on the material recieving the heat all depends on the insulating factors of that material. heat will allways win in the end given a constant heat source.

Sufficient heat can transfer through most mediums made of matter. Think of our sun and outer space. Even though there is a vacuum between the sun and Earth, the sun's heat still manages to reach Earth.

Your dryer is not perfectly insulated (nothing is). So, the heat in the clothes warmed the dryer, which warmed the air around it, which warmed the walls, which warmed the air around your house, which warmed the earth, which lost the heat to the universe. If you notice, the room the dryer is in, get warm when it is running.