…for yourself, the environment, and your wallet.  For less than $6, you can purchase an air conditioner coil cleaner.  It’s sold in a spray-paint can (that part may not be great for the environment, but it has no CFCs).  Cut the power to your outside a/c unit and spray the foaming cleaner on the coils.  It’s supposedly self-rinsing, but I went ahead and hosed it off (the instructions permit rinsing).  As soon as I cut the electricity to the outdoor unit back on, the difference was readily apparent.  Before, our a/c unit clanged around and we wrote it off as being an old (15-20 years) unit.  Now, it’s humming to the point that Tovah said it’s purring.

I shudder to think how much money we lost in electric bills and how much energy we wasted because we didn’t know to do this.  Six bucks was a cheap fix.

Kudos to Nick for the recommendation.  I purchased my can at Lowe’s, but I understand it’s available at any hardware store or home improvement big box store.