At night cool your house down by opening windows and using windows fans. I have a two story house. Heat rises so I'll place window fans blowing out in the upstairs windows and fans blowing in upstairs. In the morning close up the windows and close curtains and shades over the windows that receive direct sunlight. If you have a room that gets hotter than the others shut the door to that room or hang a curtain over the doorway. My hot water tank is in a first floor room so I isolate that room and leave the windows open. Have a ceiling fan? Make sure it's blowing in the right direction. Most have a switch so you can alternate direction it blows the air. Not always practical but soaking your feet in cool water will lower your body temperature. Much like coolant cools a combustible engine car your blood circulates through your body distributing heat. Personally I avoid using AC while driving as much as I can. It's my opinion that when we get used to such comforts we suffer without them. I do have a window unit but use it only on the hottest nights. One last thought. Some lights or appliances in your house may give off a lot of heat, feel around them to find which ones do and switch them off. You can't do anything about your refrigerator (gives off a lot) I had a plasma TV that felt like a space heater and also used a lot of electricity