The Most Efficient Air Conditioner Settings

Comfort Is King

• The truth is, it is more important to be comfortable in your own home than it is to save $3 to $5 each month on your bill. Because that is usually the kind of difference you are looking at. Yes, the $50 or so you save by the end of the year can come in handy, but you may find it isn't worth it to sweat in your living room for several months out of the year to make it happen. Remember that comfort is your No. 1 priority. Once you decide which settings make you comfortable, then try to adjust them slightly to see if you can shave off a little energy usage.

Maximum Efficiency Temperature

• If you just want a simple answer to solve your air-conditioner efficiency problem, then you can disregard everything else and set the thermostat to the number that tends to provide maximum efficiency. According to the APS Residential Service energy website, you should set your central air-conditioner thermostat to 79 degrees Fahrenheit for your unit to get the most bang for the buck. This setting keeps your home cool enough to live in with reasonable comfort and uses less energy. You can save an additional 2 or 3 percent on your cooling costs for every degree you go above 80, but the house may be very stuffy.

When You Are Away

• To further improve your air-conditioning efficiency, don't cool the house while you are gone. APS recommends setting the temperature at 85 degrees Fahrenheit when you are away from home to reduce the amount of energy used. But green living website Rodale suggests you just turn off the unit entirely when you leave. The system works most efficiently when it runs at full blast anyway, so making it work hard to cool the house down when you get home is not a bad thing.

Fan Switch

• You can set most fan switches on the thermostat to "on" or "auto." Setting it to "auto" means the fan only comes on and blows air through the vents when the system is producing cool air. If it is in the "on" position, it continues to blow between cooling cycles. This could make the air more comfortable and keep temperatures even, but it is still more efficient to use the "auto" setting and let the fan turn off between cycles.

Programmable Thermostats

• You can invest in a programmable thermostat to take air-conditioning efficiency to another level. These programmable systems allow the homeowner to set the thermostat to different temperatures throughout the day according to his needs. This way, you never have to worry about forgetting to turn off the air when you leave or remembering to turn it down when you go to bed. You can customize the settings to do all of this for you. It can even be programmed to keep the house cooler on your days off for your personal comfort.