Why Does Turning on the Air Conditioning Cause a Significant Drop in Car Power?
2 Answers
The following are the reasons why turning on the air conditioning causes a significant drop in car power: 1. Low engine power: Unlike household air conditioners, car air conditioners are usually directly driven by the engine, with power typically ranging from 1KW to several KW. However, when the air conditioning is turned on, the blower is usually also activated for air circulation; otherwise, true cooling cannot be achieved. Although a car's power can typically reach 80KW, that is the engine's maximum power, and in actual use, it often falls far short of this value, especially at low speeds, where the power is often only utilized at 30-40%. 2. High proportion of engine power at low speeds: In addition to overcoming the vehicle's driving resistance, the engine's power is also needed to charge the battery to compensate for the consumption of car appliances (including the air conditioning blower, lights, radio, etc.), as well as for power-assisted systems like steering and braking. Therefore, although the air conditioning's power may seem small overall, it occupies a large proportion at low speeds and during startup, making it easy to feel a noticeable drop in power.
It's indeed quite common for a car to experience reduced power when the air conditioning is on. The main reason is that the AC compressor adds extra load to the engine, diverting some of the power that would otherwise drive the wheels. It's like suddenly carrying a backpack while running – you'll definitely feel more tired and naturally slow down. For small-displacement vehicles with limited engine power, the power loss is more noticeable with AC on, especially during hill climbs or acceleration for overtaking when the car feels sluggish. I've also noticed that in summer, when the AC is set too cold, the compressor bears heavier load. Combined with reduced engine efficiency due to high temperatures, this double whammy makes the power drop even worse. My suggestion is to moderately lower the AC fan speed in congested urban traffic or manually switch to external air circulation to reduce load. In the long run, keeping the AC system clean can also minimize unnecessary power drain.
