Wouldn't the drag caused by having the windows down be just as uneconomical as having the ac on, if not more uneconomical?

I think someone did some calculations and said that (for normal motorway driving), both were as bad as each other. Although the Fabia's air con is never fully disengaged, so you might as well leave it on all the time

Chris

Aircon or open window? Fuel cost - MoneySavingExpert.com Forums

Chris

mythbusters tackled this not so long ago, at 45mph (i think) the windows open was a lot more fuel efficient than aircon

But on a hot day you will not get the cooling of air con with just the windows down

mythbusters tackled this not so long ago, at 45mph (i think) the windows open was a lot more fuel efficient than aircon

Surely that depends on the car as aerodynamics will have a large effect on this.

Also it would be affects by other factors such as strength and directions of winds, deflectors etc fitted.

Also it would be affects by other factors such as strength and directions of winds, deflectors etc fitted.

And the type of car they tested - a lot of US cars have really hefty aircon systems on them...

Rob.

I measured the mpg's over four full tank fills, two without air-con and two with air-con. I noticed a loss of between 0.5 and 1 mpg over the whole tank, but the car had a lot more condensation on the inside without the air-con on, so decided its not really worth driving around with it off. Now I'm not suggesting that I drove the same way on the same roads for all the tanks, additionally the weather wasn't consistent., so its not very consistent.

So, just drive around in the cool, comfort and quiet of an air-conditioned car. Just use the windows for when you need to ask directions, or if your kerb crawling :eek:

im only saying what i saw, they used 2 identical vehicles with 5 gallons of fuel drove around a track until they ran out, the windows down got and extra 15 miles!!!

and they were very large 4x4 so if anything areo dydnamics was against them

And the type of car they tested - a lot of US cars have really hefty aircon systems on them...

And what temperature the "air con" is set to.........!!!

Chris