The most energy-efficient temperature setting for your air conditioner during the summer is around 21 degrees when you are at home and awake. When you are away from home or asleep, it is recommended to set it higher.

Air conditioning filters should generally be changed every 30 to 90 days. The frequency can depend on factors such as the type of filter, air quality, and whether there are pets in the home.

Common signs include reduced cooling efficiency, strange noises, bad odors, water leaks around the unit, and unusually high energy bills.

The efficiency of an air conditioner is often measured by its Seasonal Energy Efficiency Ratio (SEER). A higher SEER rating means greater energy efficiency. Modern air conditioners typically have SEER ratings ranging from 13 to 21.

An oversized unit can cool the space quickly but may not adequately remove humidity, leading to a damp or clammy feeling. Conversely, an undersized unit will struggle to cool effectively, leading to increased wear and tear and higher energy usage.

Regular maintenance of the AC unit, including cleaning or replacing filters, is essential for maintaining good air quality and preventing the circulation of dust, pollen, and other airborne particles.