Luckily for us we live in southern New York state and seldom get days so hot that cooling is a concern. However, at various points we've lived in both Florida and Oklahoma and certainly know about heat. But recently we've have had a serious heat wave through all the northern states too. People need ways to Beat this heat!
One thing I've learned is that the central principle in managing heat is:
It will rise and rise no matter what you do – as we northerners who have very warm heated ceilings all winter will be happy to tell you.
The second principle of cheap heating is that heat is transmitted by infrared rays of the sun. Just like a heat lamp.
So the fundamentals of cheap cooling involve:
1) Letting heat rise out of the building
2) Blocking infrared solar rays
One can let heat rise in a number of ways. One of the most simple is to let the hot air move up unimpeded to the second floor and then up to an attic space where, a preferably solar powered, attic fan will whisk the hot air out of the house. Ceiling fans can help in this effort if the blades are pitched in the right direction. Most are set to drive warm air down in the winter – not whisk hot air up! So make sure the fan blade is pitched properly, and then guide the air into a higher space and out of the building. If you are an apartment dweller with no attic access, then pull the upper casing of your window down and use a fan to blow air out from the higher level where the hot air will naturally collect. Heat rises –use this to your advantage.
The second part of blocking infrared rays can be as simple as planting deciduous vines and trees to block sunlight on south facing windows. However, obviously it takes time to grow trees and bushes. Apartment dwellers don’t have these options. So one block of the infrared rays of the sunlight is to put those light blocking films on the windows. They can be quite inexpensive and since they adhere with just static pressure you can pull them down to let winter light in. Shade screens can serve a similar purpose and long term are cheaper than a yearly application of light blocking film. In a pinch reflective materials like aluminum foil will reflect light away from the windows. It depends on your circumstances and level of prior preparation. Awnings are nice old fashioned solutions also.
In really hot areas where the options I mentioned are not available to you, simply raising the temperature at which the house is kept by air conditioning will save you money. Seventy-five to eighty degrees is not that uncomfortable for most people and can save people lots of money over the frigid 65 that many people place their summer temperatures to.
We lived in the desert part of western Oklahoma with just a ceiling fan and attic fan and the house never got over 80 degrees F --- even when out side it was 103 degrees F or more!!! We partially opened the attic access, used the ceiling fan to drive the hot air upwards, and then vented it out of the attic with a fan. We did have trumpet vine on the south side of the house which helped with south shade, but otherwise we were completely exposed to the sun on a rocky hillside. So I know these techniques work.
Fans can be bought cheaply at garage sales and discount stores.