If you have an older central air conditioner, you might choose to replace the outdoor compressor with a high-efficiency unit, or replace the entire system.
Today's air conditioners use up to 40% less energy to produce the same amount of cooling as those made just 10 years ago. Look for an ENERGY STAR rating and a Seasonal Energy Efficiency Ratio or "SEER" that is above 13 (the higher, the better).
If possible, install your new unit in the shade, which can allow it to run 10% more efficiently.
