I'm not sure that it would he equivalent - the AC has to fight a smaller temperature difference between outside and inside. Also, I am not sure how much it'd really save for the extra complexity. A lower maintenance way of improving overall efficiency could maybe be some way of capturing that heat to warm water a bit, so that could save your water heater some work by preheating it perhaps. That would keep all plumbing internal, and the fridge may even fight a smaller temperature difference, since tap water is usually cold. Though now if your water heater and "warm water" tank are full what do you do for the fridge? I do think that "better insulation for the house" or "just a more efficient fridge" probably trumps any of these changes in terms of energy saving for your investment in many cases.