How much evergy does central air conditioning save?

It depends on your climate and how much you use the air conditioning per this site:

“Room air conditioners cool rooms rather than the entire home. If they provide cooling only where they’re needed, room air conditioners are less expensive to operate than central units, even though their efficiency is generally lower than that of central air conditioners.”

That really depends on how energy efficient your AC unit is rated; The higher the SEER (Seasonal Energy Efficiency Ratio) the bigger the energy savings. There’s a formula for how to calculate those savings in the link I included above.

Good Luck!
R

I don’t know if central necessarily saves money at all. I have a friend who has a place with window air-conditioning units, and he said he saves money over his last place, which had central air.