Sas and Lynn, well having basements are a joy, my fuge/sump is down there, no mess with water changes, bu runs 60* all year round so helps in the summer but not the winter as far as tank heating/cooling. Putting the chiller in the garage is going to put a load on it as far as that bottled heat to cool the freon in it, and just add more heat to the garage and even make it more ineficient, it would be better out side. In the garage just a down spiral as far as temps. It sounds like you are in a no win situation. An AC cooled garden shed? for this stuff? New thought!!!!! Work but as I tell my clients "I can do anything, I am an engineer, as long as you can write the check"!!!!!!!!