It might surprise you to know that buying a bigger room air conditioning unit won’t necessarily make you feel more comfortable during the hot summer months. In fact, a room air conditioner that’s too big for the area it is supposed to cool will perform less efficiently and less effectively than a smaller, properly sized unit. This is because room units work better if they run for relatively long periods of time than if they are continually, switching off and on. Longer run times allow air conditioners to maintain a more constant room temperature. Running longer also allows them to remove a larger amount of moisture from the air, which lowers humidity and, more importantly, makes you feel more comfortable.
Sizing is equally important for central air conditioning systems, which need to be sized by professionals. If you have a central air system in your home, set the fan to shut off at the same time as the cooling unit (compressor). In other words, don’t use the system’s central fan to provide circulation, but instead use circulating fans in individual rooms.
Whole house fans help cool your home by pulling cool air through the house and exhausting warm air through the attic. They are effective when operated at night and when the outside air is cooler than the inside.
Set your thermostat as high as comfortably possible in the summer. The less difference between the indoor and outdoor temperatures, the lower your overall cooling bill will be.
Don’t set your thermostat at a colder setting than normal when you turn on your air conditioner. It will not cool your home any faster and could result in excessive cooling and, therefore, unnecessary expense.
Set the fan speed on high except in very humid weather. When it’s humid, set the fan speed on low. You’ll get better cooling, and slower air movement through the cooling equipment allows it to remove more moisture from the air, resulting in greater comfort.
Consider using an interior fan in conjunction with your window air conditioner to spread the cooled air more effectively through your home without greatly increasing your power use.
Don’t place lamps or TV sets near your air conditioning thermostat. The thermostat senses heat from these appliances, which can cause the air conditioner to run longer than necessary.
Plant trees or shrubs to shade air conditioning units but not to block the airflow. A unit operating in the shade uses as much as 10% less electricity than the same one operating in the sun.
You can save as much as 10% a year on your heating and cooling bills by simply turning your thermostat back 10% to 15% for 8 hours. You can do this automatically without sacrificing comfort by installing an automatic setback or programmable thermostat.
Using a programmable thermostat, you can adjust the times you turn on the heating or air conditioning according to a preset schedule. As a result, you don’t operate the equipment as much when you are asleep or when the house or part of the house is not occupied. (These thermostats are not meant to be used with heat pumps.) Programmable thermostats can store and repeat multiple daily settings (six or more temperature settings a day) that you can manually override without affecting the rest of the daily or weekly program