answer:There are newer A/C units that mount on the walls of rooms inside the house. Some even follow your body and blow the air right at you. I don’t know brands, but yes, there’s new stuff. A swamp cooler is a simpler device that only works in low humidity. Basically, it’s outside air that is sucked into the house through large wet pads. They require maintenance that is sometimes a pain in the ass both at the start of the summer and at the end of the summer, although there is usually no shortage of handymen who will take care of this for a fee. Air conditioning is more properly referred to as refrigerated air. It’s the same principle as your refrigerator. There’s usually no maintenance. Flip a switch and you have air conditioning. Swamp coolers are cheaper to buy and use less electricity, but also use a good quantity of water. Swamp coolers are literally useless if it is relatively humid. Air conditioners are more expensive to buy and use more electricity (and no water). I have no idea what room units would cost. Reroofing with the new, white roofing material, which is expensive, will also significantly cool your house in the summer.