During late Summer, I routinely add several bags of ice from 7 Eleven to keep the temp below 86F, particularly when preparing for a water change. I turn the heater settings down by 4-5 degrees to allow the tanks to cool down during the night...so they can absorb more heat during the following day. I turn off the tank lights and simply illuminate with the garage lighting. Finally, during water changes, I circulate the water within the tank with a pump to facilitate oxygenation when the filters are turned off.
floating bags of ice (treated water) works great.. of if you have fish that might make a mess of themselves with a plastic bag.. you can just hold the bag under hot water for a few seconds and pull it off
um I work outside in the heat as long as the house is cooler than outside it's okay by me. currently I have fans to keep the house cool. my tank heaters are for odd nighttime temp drops. After the first few hot days the heat doesn't bother me anymore granted i prefer 75 but 80 is fine I only get grumpy if it clears 85. much prefer that to the subzero temps in the winter.
also I am exhausted at work if the difference between home and outside is to great in the summer as my body is not used to the heat