Potatoes and Heat

Jacket potatoes taste better when they're roasted in the oven than in the microwave because the heat slowly roasts them from the outside. The microwave causes the potatoes to heat up from inside out. In winter I don't care too much about the oven being used because the heat is used twice, it cooks the food and helps to heat up the home. The thing I was wondering was. 

How long does the heat stay there? The heat energy is transmitted from molecule to molecule but it doesn't move in a straight line, some of the heat energy would zig zag and even travel back into the oven from the edge of the room. The way I look at it is energy released in the core of the sun slowly moves from the core to the sun's surface, the journey can take millions of years because the photons don't go in the straight line, they bounce from molecule to molecule in a tangled random route, when the photon finally gets to the sun's surface, it takes just 8 Minutes to move across space to our planet. I thought similar things would happen with an oven, some of the heat released travels around the room for 2 or 3 years before finally leaving the room; most of the heat would escape in less than 2 hours but a tiny.portion of the heat energy would remain there, perhaps 0.00001 % would still be there a year later.