does air conditioning in a car use much petrol? and if so why?

Question

oh well so it does a little....its a small price to pay for my comfort.

Answer 1

Just 1 thing to point out, on most newer vehicles, aprox. mid 90's and newer, the fuel consumption caused by using the A/C, is almost exactly the same as the extra fuel used to compensate for the drag caused by having the windows down. So basicly, take your pick, use the A/C or have the windows down, you'll use the same ammount of fuel either way.

But yes, the A/C compressor is run by a belt in the engine. When you turn on your A/C in the vehicle, a small clutch on the pully engages and starts making the engine turn the pully. Having the extra load to turn will cause more fuel consumption. This added consumption will be more noticeable at idle where is it having to adjust its own fuel flow in order to maintain a safe idle speed. Once you hit the accelerator, the torqe of the engin increasing will almost completely overtake the added stress. meaning, that on acceleration, your A/C will not have a great effect on your fuel economy, however, once you are at speed and cruising, there will be a slight increase in the fuel usage as your engine is not in hard acceleration. Basicly, idling is the worst for A/C, and overall, using the A/C is equilivent to rolling your widows down, so if you bought a car that has A/C, you didn't buy it so you can never use it, go ahead and use it.

However, when it comes to fuel conservation, using the A/C shouldn't be yourfirst concern. Remove excess weight, anything you carry that you don't need will cause you to use more fuel, check your tire pressure and ensure they are properly inflated. Get a tuen up, new plugs, plug wires, oil changes every 3 moths or 3K miles, and use a bottle of fuel system and injector cleaner. Hope this has helped, good luck.

Answer 2

Actually most cars 2 hp is used to run the compressor. So running with the windows down makes the wind turbulance almost equal to the power the A/C draws. Slippery shaped cars benefit more when the windows are closed. Air conditioning also allows driver passenger confort. Dehumidifing the cabin air and taking heat out from the engine wall and floor really helps. And the added plus of being able to hear that expensive CD/MP-3 player

Answer 3

Yes, the equivalent of a drop of 1 or 2 mpg in the fuel use. This is because the air-con has a compressor like in a fridge and this needs power to drive it. Generally you would lose more mpg by driving with the windows open as this spoils the airflow over the car and increases drag.

Answer 4

Yes. When not is use the pump is disengaged, once it is selected it is usually driven by a belt which puts load on the engine and can soak a couple of horse power. As for consumption try running the same distance with and without a/c and check your consumption.

An alternative is to drive with windows open however the air entering the vehicle also acts as a brake to some extent.

Answer 5

Using the A/C does use more petrol because you are engaging the a/c compressor causing the engine to work harder. My car (Cadillac ElDorado) has an instantaneous fuel economy gage and when I turn on the a/c it drops the econonmy about 3-4 mpg.

Answer 6

Interesting question! Anything that takes power from the engine has to be paid for, either in energy reduction or, and as a consequence, in more petrol being used. I estimate that my petrol consumption goes down by 10% when I use the aircon and that is confirmed by the onboard computer. The hotter the outside temperature, the harder the aircon works with less fuel economy. But anything that takes power from the engine can increase mpg, such as headlights, wipers, heated screens, heating fan etc .... just let your engine idle and watch as the tickover speed drops when you switch these items on .... you have to increase the engine speed to maintain battery charge and hence more fuel consumption. The aircon is essentially a belt-driven power accessory but the effect is exactly the same. I understand that diesel engines suffer less as they work on higher torques in general and sense the power reduction less, so in that sense, diesels may be considered greener to the atmosphere. My personal gripe with aircon in a small capacity petrol engine is that is affects performance considerably and hence the increase in fuel consumption necessary to maintain road speed etc.

Answer 7

On a Jaguar xjs about 2 mile per gallon approx 10 per centThe reason for extra fuel consumption is the extra load put on the engine by the air con compressor and clutch when engaged

Answer 8

In older cars, the drainage was dramatic. Newer vehicles are not as bad as far as fuel is concerned. Technology has come a long way. On long hills is where you would see an impact on fuel and current drainage. Shut that bad boy off on that long climb to your local make out point!.

Answer 9

The AC in a car is driven by belts attached to the mechanism that turn the alternator. When it is switched the belts drive the refrigeration unit so more fuel will be used in order to drive these belts.

Answer 10

It puts a load on the engine to run the compressor and the engine has to work harder because of the increased electrical load as well...using more gas. Usually, it's 2 or 3 less miles per gallon or more depending on the engine size, whatever that converts to in metric.