Consider two identical rooms, one with a refrigerator in it and the other without one. If all the doors and windows are closed, will the room that contains the refrigerator be cooler or warmer than the other room? Why?

Answer 1

Refrigerators transfer heat from the contents inside (food and drinks) to the air outside. In addition, the electrical energy needed to run the refrigerator's compressor winds up as heat in the room. So what do you think the answer is?

Answer 2

The room that contains the refrigerator will be warmer than the other room

Answer 3

That is correct!

Did you ever notice that air conditioners must exhaust heated air on the outside of the buiding?

If they didn't, they would end up heating the room. It would be like putting a refrigerator in the room.

It is a consequence of the second law of thermodynamics.