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.
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.
Set your thermostat as high as comfortably possible in the summer. The smaller the difference between the indoor and outdoor temperatures, the lower your overall cooling bill will be. Avoid setting 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. 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.
If your air conditioner is old, consider purchasing a new, energy-efficient model. You could save up to 50% on your utility bill for cooling.