FIY: In the state of New York, where electricity costs $0.246 / kWh, it would cost $1,400 to run your 14 SEER central AC for a whole year. A more efficient 18 SEER central AC would cost $1,134 per year.

The saving from upgrading to a higher efficiency system would be $266 per year, and it will take just 6.2 years to recoup the extra upfron cost.