How much does using car air conditioning affect fuel consumption?

[Gertrude]

It differs by 20%. The car air conditioning consumes about 20% of the engine's power, so using it will utilize a portion of the engine's power, leading to increased fuel consumption. The exact increase in fuel consumption depends on the car's displacement and speed. Below are specific details about fuel consumption: 1. Fuel consumption depends on road conditions: Urban driving, short trips, and stop-and-go traffic all lead to increased fuel consumption. 2. Fuel consumption depends on driving habits: Sudden braking, fluctuating speeds, prolonged engine idling, aggressive acceleration, and long-distance driving at high speeds in low gears can all increase fuel consumption. 3. Principle of vehicle fuel consumption: The fuel consumption per 100 kilometers is an indicator of a vehicle. Driving slower than the optimal speed increases fuel consumption per 100 kilometers, while driving faster than this speed has the opposite effect. If the engine speed is maintained within the same safe range, the hourly fuel consumption remains the same regardless of the vehicle's speed.

[StCaleb]

When driving my family's 1.6L car, I noticed the fuel consumption spikes when using AC in summer. Especially during traffic jams when idling with cold air on, the dashboard shows an extra 2L per 100km. You can clearly feel the engine shake when the compressor kicks in. It's slightly better on highways - cruising at 80km/h adds about 0.8L extra. I later asked a mechanic specifically - the compressor takes 10%-15% of the engine's power, equivalent to carrying two extra passengers. Now when it's not too hot, I just roll down windows for ventilation. Only when temperature exceeds 30°C do I press the AC button - this saves enough fuel per tank for two cups of milk tea.

[XavierDella]

Three years of DiDi driving experience: Air conditioning costs at least 12 RMB extra per 100km. Most noticeable in my hybrid Corolla - the engine frequently starts to recharge when AC is on. During morning rush hour from Pudong Airport to Jing'an Temple, fuel consumption shows 5.3L without AC but jumps to 6.8L with AC. A word to new drivers: don't keep windows closed with external circulation just to save fuel. Last summer, a passenger got heatstroke and vomited on my backseat - the cleaning cost equaled half a tank of gas. Maintaining tire pressure at 2.5Bar helps reduce compressor load, this trick works well.

[DelPiper]

Just tested my Model 3: Using AC consumes 18% more power than ventilation mode. Driving on the inner ring elevated road with auto AC at 23°C, the energy consumption per 100km jumped from 13kWh to 15.3kWh. Gas cars are even worse - my friend's old GL8 Landry burns 3L more fuel when AC is on. Actually, the most energy-intensive scenario is blasting strong cooling after the car's been baking in the sun. Now I always use remote start to precool, setting it to 25°C before entering - most efficient. Applying quality heat-rejection film on the windshield can also save 15% AC energy consumption, proven effective through personal testing.

[JaylaRose]

Experience from repairing thousands of cars: Three key factors determine AC fuel consumption. Small-displacement naturally aspirated engines suffer the most—it's not uncommon for sub-1.5L cars to see a 30% fuel increase when AC is on. Take the Fit for example: the moment its compressor engages, engine RPM instantly jumps by 500. German turbocharged cars fare better, though faulty variable-displacement compressors in older Audi A6L models can worsen fuel economy. Modified performance vehicles require special attention—last week, a tuned Civic experienced knocking with AC on, traced to a stuck AC relay overloading the alternator. Recommendation: Shift to Neutral at traffic lights to reduce compressor strain.