Here are some of the most important and cost effective ways for you to lower your energy bills when the thermometer climbs past 80ºF. It Pays to Watch Your Cool Out with the old New, Energy Star® air conditioners use at least 10% less energy than conventional models. Many are also programmable, so you can change the level of cooling the AC provides throughout the day. Right size your window AC Window units operate most efficiently when they run for a longer period of time. Installing a unit that is too big for the room will cause it to turn on and off more frequently for reduced efficiency. Adopt a fan plan For window AC units, use a desk or floor fan to help circulate the cool air which will allow you to turn the unit to a high temperature. Freedom fan For greatest efficiency, make sure the AC fan unit outside your home is free from leaves, debris and other materials so air can circulate around it freely. Charge it AC units that are low on refrigerant work harder and use more energy to cool the home. To keep yours working efficiently, have an AC technician give whole-house and portable AC systems a maintenance check once each year. Get with the program For homes with whole-house AC, install setback thermometers. During warm weather, program them to 80ºF when you're home and 85ºF when you're not. Be sure thermostats aren't located above lights or a TV, which can make them detect the room is warmer than it is. A real turn off If you're going to be gone for a day or more, don't forget to turn the AC off. Close the curtains Keep the sun out, and the room temperature will be lower. Change the filter During the cooling season, replace or clean the AC filter once a month. You'll knock off 5% of your energy bill. Seal ducts If you have whole-house AC, have a technician test the air ducts in your home for leakage. Sealing ducts can save up to 25% in cooling costs. Is there a fan in your attic? Installing a whole-house fan draws cooling air through screened windows and doors and exhausts it through the attic vents. In the evening, a whole-house fan can significantly reduce the inside temperature of your home without the need for AC. Ceiling fans can be very cool Ceiling fans are becoming increasingly inexpensive and there are more design choices than ever before. Best of all, they use about as much power as a 100 watt light bulb while cooling a room up to 4ºF. Seal your envelope The exterior walls, the floor and the ceiling of your home form an “energy envelope.” Keeping it well sealed will help lower cooling costs if you operate an AC system. Learn more. Put your foot down Making sure you have at least one foot of insulation in the attic will greatly reduce the temperature in your home while also reducing the load on your air conditioner. Learn more about adding attic insulation. Pool your savings You'll save significantly if you can reduce the time your pool filter, skimmer and heater need to run. One way to achieve all three is to keep your pool covered when not in use.