1. The problem statement, all variables and given/known data Hi. I know that a refrigerator and heat pump do the exact same thing, which is transferring heat from a cooler area to a warmer area. This is what I've gathered from my university notes. My question is: is it necessary for the area it's transferring FROM to be COOLER than the area it's transferring TO? 2. Relevant equations 3. The attempt at a solution I don't think so, because when you buy a refrigerator, before you switch it on, the air INSIDE it could be WARMER than the air outside (in the atmosphere). OR, if you simply switch off the fridge and light a fire in it and let it warm up inside, once you switch it on, it will still perform the same function of just transferring the heat from inside to the atmosphere, even though you heated the inside of the fridge until it became hotter than outside. Unless the author was referring to them in the long run, after a significant time of being on.