What is the most fuel-efficient temperature setting for car air conditioning?

[McJuniper]

The most fuel-efficient cabin temperature is 26°C. Proper air conditioning usage tips: 1. Optimal timing for turning on AC: The first action after entering the car should be opening windows and activating the AC's external circulation to expel hot air. Switch to internal circulation only after the cabin temperature drops. 2. Turn off AC during prolonged stops: When cabin temperature becomes comfortable, temporarily turn off the AC and open windows for ventilation. 3. Never turn off engine before AC: Several minutes before reaching your destination, turn off the AC while activating natural ventilation to allow temperature recovery in AC ducts, eliminating temperature differentials with outside air and maintaining system dryness. 4. Alternate between circulation modes: While internal circulation can be used, avoid prolonged operation. Initially use external circulation when starting AC, then switch to internal after cooling, periodically alternating between both modes.

[DiCharlie]

Setting the car air conditioner to 26-28°C is the most fuel-efficient, which I think is quite important. The air conditioner operates via the compressor, and once the compressor starts, it consumes engine power, naturally increasing fuel consumption. If the temperature is set too low, say 22°C, the compressor has to work continuously, burning fuel faster. Setting it to 26-28°C reduces the compressor's activation frequency, significantly lowering fuel consumption. I've tested this with several cars myself—setting it to 28°C in summer when external temperatures are high works well, keeping the cabin cool enough while saving about 10% on fuel. Remember, on highways, keep the windows closed for more efficient AC use; at low speeds, you can occasionally open the windows for ventilation. Regularly cleaning the AC filter also makes cooling more efficient, indirectly saving fuel. In short, balancing comfort and economy is key—there's no need to make it too cold.

[AlejandroFitz]

When our family goes out for a drive, setting the air conditioning at 27°C is the most fuel-efficient and comfortable. We used to set it at 24°C, and the fuel gauge would drop rapidly. Later, we tried 27°C and saved a lot of fuel. In the scorching summer heat, I usually roll down the windows for 2 minutes before turning on the AC to let the hot air escape, so the compressor doesn’t have to work too hard. On long trips, setting the AC to 27°C with recirculation mode keeps the fuel consumption low and the car cool. After driving for so many years, I’ve realized that setting the temperature too low puts more pressure on the compressor, wasting fuel. On the highway, never roll down the windows—it increases wind resistance and burns more fuel. This method is simple and practical, and even my wife says it’s cost-effective.

[Ralph]

Setting the air conditioning to 26-28°C is the most fuel-efficient, as I've specifically tested. When the compressor's cooling is set lower, it starts frequently, consuming more fuel; at 26-28°C, the compressor's working duration is shortened, saving fuel. Temperature changes significantly affect fuel consumption—22°C uses 10% more fuel than 28°C. On highways, setting the AC higher is more economical, as opening windows increases drag. Regular maintenance, like changing filters, prevents AC blockage, low efficiency, and extra fuel consumption. The golden temperature zone offers comfort and savings—worth it.