turn your a/c on, its summer!! i never let my house get hotter then 75F, even when your not there, its gonna cost you more to turn the a/c on and off then it is to leave it on constantly, it will also cost you more to run a chiller then to just drop the ambient temperature, chillers put off a lot of heat, which in turn will make your a/c work harder, unless you like a
hot house, and ass for the ice ideas, there great ideas, but you will get sick of replacing the ice after awhile, those 2 liters melt pretty fast, i had the same problem with a hydroponics setup and those 2 liters lasted me no more then an hour or 2, a few extra bu, cks on the power bill is definatley worth your tank
IMO