The average temperatures for the first six years of the 1990s already make this the warmest decade ever recorded in the history of Earth. The United States is the number one contributor to global warming. The United States has been the leading emitter of greenhouse gases for decades. We emit more carbon dioxide than any other country in the world. The most effective method to cool your home is to keep the heat from building up in the first place.
Secondary sources are heat-generating appliances in the home and air leakage.
A summary of pointers follows, for more detailed information visit the DOE's energy facts sheet Cooling Your Home Naturally. About a third of the unwanted heat that builds up in your home comes in through the roof. One good solution is to apply a reflective coating to your existing roof available at your local hardware store or lumberyard. Another way to reflect heat is to install a radiant barrier on the underside of your roof. A radiant barrier is simply a sheet of aluminum foil with a paper backing.