Yes, air conditioners generally use less electricity when they are set to a lower setting. The reason for this is that air conditioners work by removing heat and moisture from the air, and the cooling capacity is directly related to the temperature difference between the air inside the room and the air outside.
When you set the air conditioner to a lower temperature, it runs for a longer time to reach that lower temperature. However, it doesn't necessarily mean that it's using more electricity than if you set it to a higher temperature. The total electricity consumption depends on factors such as the efficiency of the air conditioner, the size of the room, the outside temperature, and the insulation of the room.
When you set the air conditioner to a higher temperature, it will turn on and off more frequently to maintain that temperature, leading to more frequent short cycles. These short cycles can result in more energy consumption because the air conditioner uses more electricity to start and stop its cooling process compared to running continuously for a longer time.
In general, to optimize energy efficiency while using an air conditioner, it's recommended to set the thermostat to the highest comfortable temperature for you. This will allow the air conditioner to run more consistently and efficiently, reducing energy usage. Also, consider keeping doors and windows closed to maintain the cool air and improve the efficiency of the air conditioner.