For residential homes, some countries set minimum requirements for energy efficiency. In the United States, the efficiency of air conditioners is often (but not always) rated by the seasonal energy efficiency ratio (SEER). The higher the SEER rating, the more energy efficient is the air conditioner. The SEER rating is the BTU of cooling output during its normal annual usage divided by the total electric energy input in watt hours (W·h) during the same period.
Your home’s HVAC system is a fine-tuned piece of machinery. Like your car, your system needs regular maintenance and tune-ups to ensure it is running reliably. Manufacturer warranties for most new systems require annual tune-ups, and for good reason: these preventative maintenance measures extend the life of your system by keeping your system running the way it is designed to run.