Why does automobile air-conditioning waste gasoline?

Question

To me it makes sense that the use of air conditioning to keep cool in an automobile would waste water and Freon. How does gasoline interact with auto air conditioning?

Answer 1

It is said that it makes your cars engine work harder. While that might be true other studies have shown that it isn't a significant amount.

Answer 2

The A/C does not waste water or freon. The a/c has nothing to do with water. The a/c is a closed system that cycles freon. However, in order to get rid of excess heat, the refrigerant must be compressed with a compressor. This takes power to do so, and that power comes from the engine. So to travel the same speed when you don't have the a/c engaged, takes more power or more fuel. And it does not make the engine less efficient. The engine efficiency has nothing to do what it operates. It just means you are using less of the engine's power to move the car. It has nothing to do with the batter, like some people are saying. The compressor is generated by mechanical power from the engine, not electricity. And the only reason those studies show you use less fuel than just having the windows down, is because those tests were done at high speeds. The aerodynamics of the car are worse with the windows down. Therefore, the loss of power due to the a/c is less then the loss of power because of high drag, but only at high rates of speed. At low speeds, the aerodynamics have little effect on vehicle drag, and the a/c will be more dominant.

Answer 3

Here's your crash course in Automotive tech and air-conditioning. Any air-conditioning system, including the one on cars, is a sealed system. Freon IS NOT being blown out of the system. Freon, just like in your refrigerator, is a coolant that helps exchange heat through a series of metal tubes called a condenser. Air is blown across these tubes and is cooled producing that wonderful stuff we love, conditioned air. (by the way, the only way air conditioning-read freon- is bad for the environment is when the sealed system leaks or is improperly handled by low skill mechanics). There is no water in the system, so no water is wasted. Any water you see dripping from the car when the air conditionaer is used is condensed water from the humid air outside the car, just like a cold coke can sweating when it is taken out of the fridge and put on a table.
That's a very basic description on air conditioning.
Here's how the air conditioning uses more fuel.
Everything on a car is ultimately powered by the engine. Even a Hybrid with its battery power must get energy supplied by the rotation of the engine to charge itself from the wheels. The battery in regular car that runs the ignition, radio, lights, power windows etc.. get charged by the engine. The air conditioning compressor is the same. The engine has a belt or belts which turn an alternator(generator) for the battery and the air conditioning pump. When you turn on the air conditioner, the engine has to work harder to turn the pump and therefore uses more gasoline as a result.
Hope that helps.

Answer 4

Their is no direct interaction. But the freon has to run through a compressor which like the power steering or even alternator runs off the crankshaft pulley. It puts a load on the engine and the engine loses a few horepower in the process.

Drag racers will run with no belts and a well charged battery just to avoid wasting the horses. They often do not even attempt to cool the engine and leave the water pump disconnected.

If you ever listen to your engine at idle after its warmed up...you can hear the engine slow down when you turn on the AC.

Answer 5

Because the A/C compressor requires energy to operate. That energy comes from a belt connected to the engine, so when your A/C is on, it places a greater load on the engine. So, in effect, you are making the motor do more work. More work requires more fuel. There's no free lunch in physics. Also, the operation of the blower motor (the fan that pushes the air through the vents in your dash) requires electricity, so the alternator also places an additional load on the engine, but to a lesser amount than the A/C compressor. Laboratory testing shows that operating your A/C diminishes fuel mileage by a significant amount. EPA ratings are done without A/C in operation.

Answer 6

The A/C compressor is ran by your vehicles engine via a belt. The compressor is a high power piece of equipment. It puts a load on your engine which makes the engine work a little harder to power it. This also depends on what kind of driving you do. If you do a lot of city driving, it could lower your mileage by as much as 6 or 7 mpg.
If you do a lot of highway driving, it can actually improve your mileage. The drag of open windows in a car on the highway will cause a larger loss of mpg than the use of the A/C.

Answer 7

The engine has to run more to produce energy for the cooling system. Thus more gasoline. Air conditioning doesnt use water, it creates it when it condenses the hot air to create cold air, the moisture is a result. The unit itself is usually cooled by the engine fan and radiator system.

Answer 8

It is not gasoline directly, when the air conditioner is turned on, the engine has to work harder to run the air conditioning compressor therefore using more gasoline.

Answer 9

To cool the air in your car it needs to be compressed. The compresser is run by a belt that is conected to your engine. So by turning your A/C on your compresser needs to be run and it takes a little more power from your engine to do so. Honestly I know in my car and living in the south the benifits of cool air outway the little amout (if any) of extra gas needed

Answer 10

The air conditioner is an accessory, which requires a lot of power. Doesn't it make sense that the high powered accessories need to consume more fuel to keep it running?

Answer 11

Air-conditioning uses gasoline because if you put it on it uses more energy from the battery and in that way your car uses more gasoline.