How much more does it cost me to use the air-con in my car?

DURING the warmer months behind the wheel the vast majority of drivers will whack on the air-con if they have it.

There’s nothing worse than a stuffy cabin, plus you can be fined up to £5,000 if you let the warmth affect the way you drive.

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But how much more does switching your air-con system on cost you versus leaving it switched off?

The AA reckons: “Air con could add up to 10% to fuel consumption – the effect is likely to be more noticeable on short trips when it’s got to work harder to cool the car in the first place than on longer journeys where it’s just keeping the car cool.

“If you return to a hot car it’s best to open all the windows when you first drive off to clear the hot air before closing them and turning the air con on – the air con won’t have to work so hard and you’ll cool the interior more quickly.

“If you’re really hung up on fuel economy then around town at low speed, driving with the windows open is an option instead of using the air con – but at higher speeds this will cause so much additional drag that closing the windows and using the air con will be the cheaper option.”

With the average tank fuel sitting at more than £100 at the time of writing, using 10% more fuel in the summer months begins to add up.

That’s why anything you can do to cool the interior of your car at lower speeds before the air-con system has to get involved is a good thing.

The air-con system has a compressor which cools the air fed through it before it’s blown into your cabin.

The compressor is powered by the engine, so when its on, the engine is having to take care of moving the car forward and cooling the cabin, as well as all the other functions around the car too.