Does using air conditioning in summer significantly increase fuel consumption?

[LaCora]

Using air conditioning in summer significantly increases fuel consumption. The reasons are as follows: 1. The higher the temperature and humidity, the greater the fuel consumption of the car's air conditioning. For example, when the temperature is 20°C and the humidity is 50%, which is a comfortable state for humans, fuel consumption increases by 10% compared to not using air conditioning. However, if the humidity doubles to 100%, meaning moisture cannot evaporate and sweat doesn't evaporate either, with water droplets forming on the car windows and walls, the fuel consumption with air conditioning on can be 20% higher than without it. 2. Using air conditioning affects engine power. To achieve the desired speed, the accelerator needs to be pressed slightly deeper than usual, which inevitably leads to higher fuel consumption. If a car's engine has a maximum power of 100 and the air conditioning compressor consumes 10, with an average daily fuel consumption of 10L, using air conditioning may increase fuel consumption by one-tenth, resulting in 11L.

[AlejandroDella]

It's true that using air conditioning in the summer does consume more fuel, which I've personally experienced. Every time the AC compressor kicks in, you can clearly hear the engine sound become heavier, and the RPM jumps up just a little bit. Especially on hot days when the car's been parked in the sun, turning the interior into a steamer, the AC has to work extra hard to cool it down. In these situations, it's not surprising to see fuel consumption increase by 20% or more. Driving about 10 kilometers in the city with the AC on can easily consume an extra half liter of fuel. However, this also depends on the car's condition—older cars with less efficient AC systems tend to use even more fuel. The worst is getting stuck in traffic with the AC running while the engine idles; watching the fuel gauge drop rapidly is truly painful.

[VonAna]

Using the air conditioning consumes fuel, which is directly related to the engine load. The power for the air conditioning compressor entirely depends on the engine. Typically, a regular car using the AC will burn an extra 1-2 liters of fuel per 100 kilometers. If you encounter extreme heat of 40 degrees Celsius with the car interior reaching 50-60 degrees, the compressor will basically run at full capacity, increasing fuel consumption by up to 20%. I've noticed that driving with a full car and the AC on is particularly fuel-intensive, especially on uphill sections. However, here's a fuel-saving tip: don't rush to turn on the AC as soon as you get in the car. First, roll down the windows and drive a few hundred meters to let the hot air escape, then close the windows and set the AC to 26 degrees Celsius with the fan speed at level two, which is just right.

[LaEsther]

Running the AC in summer definitely consumes more fuel, but it depends on the situation. City traffic is the worst, especially during stop-and-go conditions. Every time you accelerate, the AC drains significant engine power. I've measured fuel consumption increases by up to 30% during rush hour. On highways, the impact is smaller since the engine operates more efficiently—using AC only adds about 10% more fuel. However, never roll down windows instead of using AC on highways, as increased wind resistance burns even more fuel. I find temperature settings crucial—setting it to 25°C saves much more fuel than 18°C. Another tip: using recirculation mode during midday drives cools the cabin faster and improves fuel efficiency.