Why does the power decrease when the air conditioning is turned on?

[OStephen]

The reasons for decreased power when the air conditioning is turned on are: 1. Poor fuel quality: When there are too many impurities or excessive water in the fuel, it naturally affects the power output; 2. Severe carbon deposit issues: Excessive carbon buildup in the throttle valve and intake pipes affects the air intake volume, preventing gasoline from fully combusting, which naturally reduces power and to some extent increases fuel consumption; 3. Damaged ignition coil: If one cylinder fails to ignite and cannot function properly, it results in insufficient power due to cylinder misfire and is accompanied by engine vibration; 4. Damaged fuel pump: A malfunctioning fuel pump affects the fuel delivery volume, ultimately leading to insufficient fuel injection into the engine and reduced engine output power.

[McElliot]

When the air conditioning is turned on, the lack of power is because the compressor in the air conditioning system needs to be driven by the engine, which directly consumes a portion of the engine's output power. Especially for small-displacement cars, which already have limited horsepower, the compressor adds an extra burden. This makes the car feel particularly sluggish during acceleration or uphill driving. I've noticed that this is most noticeable when starting in the city or overtaking on the highway with the AC on during summer. Don't underestimate this impact—increased compressor load can also raise engine temperature, affecting overall performance. The solution is regular car maintenance, such as checking if the AC belt is worn or if the radiator is clogged. Ignoring these minor issues can worsen the power loss. If necessary, turn off the AC for a few minutes before climbing a hill and turn it back on once the power returns. Choosing a car with a more powerful engine can also alleviate this issue, but most family sedans have to face this reality.

[McAxel]

It's quite common to experience reduced power when the AC is turned on, as the compressor activation means the engine has to divert some power to an additional task. This is particularly noticeable in congested city driving with frequent acceleration and deceleration, where continuous AC operation adds to the engine load, creating a pronounced sluggishness. I've felt this acutely when driving manual transmission cars—climbing hills in low gear with the AC on makes the vehicle labor like it's gasping for breath. Older or smaller-displacement engines perform worse, though newer cars optimize this with intelligent systems. To mitigate, maintain your vehicle in good condition by cleaning air filters and cooling systems for efficient engine operation. If this occurs often, try lowering AC fan speed or temperature settings to reduce compressor power demand; on long trips, precool the cabin and use recirculation mode to maintain temperature, avoiding frequent power fluctuations. Developing these habits can significantly ease driving discomfort.

[SanSarah]

Insufficient power when the air conditioning is on mainly stems from the compressor being driven by the engine, which diverts some power. Small-displacement vehicles are most sensitive to this, with noticeable jerking during uphill climbs or sudden acceleration. I recommend checking the air conditioning system for abnormalities, such as excessive refrigerant or loose belts, which can exacerbate the issue. Regular maintenance should not overlook cleaning the condenser or cooling fan. Adjust driving habits by avoiding sudden throttle presses when the air conditioning is on and choosing to turn it on during smooth road sections.