This is the third summer of usage for our air conditioning unit. It's an
external unit that works through the central forced air system.

This summer the KW hrs usage is up about 60 pct over the last two summers.
Obviously, settings and weather influence it, but I'm wondering if it could
be that it needs maintenance of some kind that would make it more efficient
and use less electricity.

Any thoughts or ideas what I should look for to make sure it's not running
inefficiently?

Gracias