Even while today's modern air conditioners are very energy efficient, there are still certain things you can do to enhance that efficiency throughout the course of your system's lifetime. These strategies will keep you cool all summer long, even if your air conditioner is a few years old. Evaporator Coil Cleaning   Inside, dust the coil with a soft brush, then spray it with a commercially available no-rinse coil cleaner (available at home improvement stores). The spray foams up before dripping into the drain pan. Using soap, hot water, and a little bleach, scrub the drain pan clean.