Regardless of your views on global warming/global climate change, there is no denying that the last few summers have been among the hottest of the last 150 years. The heat waves of 2003 claimed thousands of lives in Europe and heat waves in 1995, 1999, and 2006 each killed several hundred here in the US. Unfortunately, for the energy conscious, one major response to the heat consumes great quantities of energy in the process.
Though air conditioners are more efficient than they used to be, they still use ozone-damaging flurocarbons and constitute up to half of a typical US household's summer energy bills. Air conditioning can aggravate health conditions such as arthritis and sinus problems, and the body becomes stressed when moving between the temperature extremes created by air conditioned interiors and hot summer exteriors. Additionally, making the body accustomed to artificial cooling can result in a weakened natural ability to cope with high temperatures.
If you already have an air conditioner, clean the filter (or replace it) regularly to improve air flow. If you are looking into purchasing one, be sure to look for an Energy Star approved model. Models with Energy Star approval use at least 10% less energy than their less efficient counterparts and save you money over the life of the machine. Check out the Room Air Conditioner section of Energy Star's webpage for more detailed analysis of what's available (http://www.energystar.gov/index.cfm?c=roomac.pr_room_ac).
If your thermostat is involved in both heating and cooling your home, try setting it to 78 degrees, and get a programmable thermostat. If programmed well, you'll conserve energy and money by only cooling your house when you are at home and awake. Annual savings with a programmable thermostat for both heating and cooling can be around $180. Other energy-saving household improvements include insulating your roof and installing an attic vent or fan. If you are planning any landscape changes on your property, consider utilizing plants that will shade your house in the summer.
When it is hot outside, be sure that your home is well-sealed to prevent the hot air from entering and your cooler air from leaving. Draw the drapes or shades to keep out the sun (or utilize awnings, which are more effective because they stop the sun's rays before they hit, and consequently warm, the windows). When it gets cooler in the evenings, open the windows and/or doors to draw in the cooler air, then re-seal everything in the morning before it gets too hot out
Inside your home, make use of ceiling fans, either instead of air conditioning, or to supplement it - ceiling fans use up to 90% less energy than air conditioners and make a room feel 7-10 degrees cooler. Turn off any unnecessary, but heat-producting appliances or electronics, like computers or the drying cycle on a dishwasher. When they are on, keep them away from the thermostat so it does not misread the temperature and work harder to cool the room. If you have incandescent lightbulbs, consider making the switch to compact fluorescents (CFLs). Incandescent bulbs use energy very inefficiently, emitting 90% of it as heat rather than light; CFLs will reduce this heat creation while using less energy
To keep yourself cool, wear loose, light colored clothing and drink lots of water. Put cool water on your pulse points (wrists, elbows, backs of knees, neck) or wear a damp bandanna. Also, eat small, light meals rather than heavy ones (your body heats up when working hard to digest them). When cooking, opt for the range, a microwave, or a toaster oven rather than turning on the oven.
And, beware the symptoms of heat illness: nausea; vomiting; fatigue; weakness; headache; muscle cramps; dizziness; cool, moist skin; fast, weak pulse; and fast, shallow breathing.