About half of the average house owner’s annual electricity expenditure about $1,000 goes to cooling and heating. Air conditioners placed in direct sunlight consume 10% more power. If you’re sitting in the sun, plant tall shrubs or shade trees nearby, but don’t close the equipment or block airflow. Place windows on the north side of the house or install awnings above it. Adjust windows or central air-conditioning for maximum efficiency. Every two to three years, call a professional to check electrical components and refrigerants. If your central air conditioner has been in use for more than 12 years, replacing it with an Energy Star model can reduce your cooling costs by 30% and save maintenance costs. The payback period for replacing a 12-year system is usually about 8 years. The efficiency level of air conditioners is measured by the SEER (seasonal energy efficiency ratio). The higher the number, the higher the unit efficiency. A SEER rating of 13 or 14 is very efficient.