A word on S.E.E.R ratings
Understanding Efficiency

What is S.E.E.R? This stands for Seasonal Energy Efficiency Ratio. Basically this ratio is the efficiency rating of a paticular A/C system. The higher the ratio the more efficient the system. A standard efficiency system today is 10 SEER and can in some cases go as high as 16 SEER. The major difference between diferent systems is condenser size. The condenser is the outside unit. The larger the condenser the more efficient the unit. The reason for this is very simple. Your compressor takes in gas and raises the temp and pressure of the gas to the condensation point. The pressure on the compressor is tremendous. This compresson stroke is where the most energy is used and in turn where your electric cost to cool come in. If the pressure in this area can be reduced then the compressor draws less power to do its job. Large condenser coils accomplish this task. More area for the refrigerant to be compressed into reduces the pressure and reduces the power required to do this. There are many factors to consider when buying high efficiency. One is the size of your home, the bigger the home the more you will save on energy, Two, how much you really use your central A/C system, Three, the size and condition of the homes duct system, Four, the condition of the furnace or air handler. The reason to consider these factors is time for "payback". If the additional cost for a super high efficiency system as opposed to a standard system is $900.00 and you use the system for three months out of the year it may take as long as ten years to recoup the intial cost of the upgrade. Meaning if you save $100.00 per season, your looking at nine years for payback. High efficiency systems are a great thing, but not in every case or every home. If you have a small rancher, with say 1200 sq ft, I would not suggest such a system for you. Your payback time may well exceed the life span on the system itself. In short, consider all these factors when your ready to purchase a new comfort system.
Your Thermostat

The thermostat is the main controller of your home heating system. It basically is a switch. Controlling when and how often that switch goes on affects the cost to heat your home dramatically. Using a set back type stat that sets the heating system back at night or when the house in not occupied is a great way to reduce heating cost. Using these type of stats is very simple, just remember dont go overboard, reduce the temp by no more then 8 degrees, any more then that is counter productive, causing the heating system to run too long to reach comfort levels. Also never use setback in the summer. Doing this will cuase higher utility bills. Consider the temp swings in winter, 70 degree indoor 30 degree outdoor, 40 degree temp difference. Summer 95 outside temp, and 70 degree indoor temp, 25 degree difference. This means less need for setback.