What is the fuel consumption ratio when driving with air conditioning on?

[SanJasper]

Driving with air conditioning on generally increases fuel consumption by approximately one gear level. For example, driving with air conditioning on in second gear consumes roughly the same amount of fuel as driving without air conditioning in third gear. It is inevitable that using air conditioning while driving will consume more fuel than driving without it. From the perspective of car configurations, air conditioning systems are mainly divided into two types: manual air conditioning and automatic air conditioning. Additional information: 1. Manual air conditioning systems are typically equipped with a fixed-displacement compressor. Adjusting the airflow volume has no relation to the compressor's operation. Once the air conditioning is turned on for cooling, the compressor operates at full speed continuously, meaning there is no concept of fuel-saving in this scenario. 2. As for adjusting the temperature in manual air conditioning systems, it merely involves mixing varying amounts of hot air with the cold air. In practical use, the interior temperature of the car rarely reaches conditions that would allow the compressor to stop running. Simply put, once this type of fixed-displacement compressor is activated, it runs at full speed without stopping, regardless of how high the temperature is set, and thus does not save fuel.