Does using car air conditioning consume more fuel in summer or winter?

[DiCalvin]

Using car air conditioning to cool in summer consumes more fuel. Introduction to car air conditioning is as follows: 1. Introduction: Car air conditioning refers to the air conditioning device installed in vehicles, which can cool, heat, ventilate, and purify the air inside the cabin, providing a comfortable environment for passengers, reducing driver fatigue, and improving driving safety. 2. Structure: It generally includes cooling devices, heating devices, and ventilation devices. This combined system makes full use of the limited space inside the vehicle, featuring a simple structure and easy operation, making it a popular modern car air conditioning system internationally. 3. Layout: Different types of air conditioning systems have different layout methods. Currently, integrated heating and cooling air conditioning systems are widely used in passenger cars. The layout typically involves assembling the evaporator, heater radiator, centrifugal blower, and control mechanism together, known as the air conditioning unit assembly.

[LaJoy]

My biggest realization from driving these years is that running the AC in summer definitely consumes more fuel. Every time during hot weather, the fuel consumption numbers on the dashboard spike because the engine not only has to propel the vehicle but also power the AC compressor, which is a major fuel guzzler. In winter, the heating system primarily relies on engine waste heat, so the compressor doesn't engage at all - turning on just the heater has almost no impact on fuel consumption. Of course, extreme cold regions are exceptions; in -30°C environments, engine warm-up time doubles, causing inflated short-trip fuel consumption, but overall it's still less impactful than running AC continuously in summer. I've tested the same route - summer AC use burns nearly 20% more fuel compared to spring/fall seasons.

[VanJeffrey]

As someone with an engineering background, let's analyze this from a thermodynamic perspective: During cooling, the compressor needs to pressurize low-temperature refrigerant into high-temperature gas, and this compression process directly consumes 7-15% of the engine's power. In contrast, winter heating essentially recycles waste heat from the engine coolant, representing energy reuse that barely increases additional fuel consumption. However, low-temperature environments also have two indirect effects: reduced gasoline atomization efficiency during cold starts and increased mechanical losses due to higher oil viscosity. Yet, the combined fuel consumption increase from these factors typically doesn't exceed 10%, far below the 15%-30% impact of summer air conditioning. In practical driving, the most fuel-efficient scenario is driving with windows closed during spring and autumn seasons.

[DelAustin]

Last week, I did the math for my cousin who just bought a car: Taking a 1.6L family car as an example, turning on the AC in summer increases fuel consumption by 1.5-2 liters per 100 kilometers, which means an extra 15 yuan per 100 kilometers at current fuel prices just for cooling. In winter, using the heater hardly affects fuel consumption. Even in -20°C weather in Northeast China, the extra fuel consumed by the engine running at high RPM during the first five minutes after a cold start won’t exceed 0.5 liters per 100 kilometers. The most fuel-intensive scenario is actually being stuck in traffic with the AC on during a southern summer. That time when I was with him in Guangzhou’s CBD, stuck for half an hour, we watched the remaining range drop by 40 kilometers. So, my advice to new car owners is straightforward: If you’re on a tight budget, use the AC sparingly, but feel free to use the heater.

[LaFinn]

I remember doing a comparative test on a long-distance trip last year: on the same 300-kilometer stretch of the Jinggang'ao Expressway, in August with the AC set at 25°C, the fuel consumption was 8.2L; in December with the heater set at 22°C, it was 6.9L. The principle is simple—the AC compressor is driven by the engine's crankshaft pulley, so cooling is like adding extra load to the engine. The heating system, however, just directs coolant flowing through the engine block into the heater core, and the blower fan consumes almost no kinetic energy to blow warm air. Although colder temperatures make engine oil more viscous, slightly increasing friction losses, it’s nowhere near the fuel consumption swallowed by the compressor. Now in the peak of summer, I try to use recirculation mode and set the temperature above 25°C—every 1°C increase saves about 3% fuel.