Windows down or A/C on?

[FusionHemi]

What will net me better mileage while driving 45-50mph?

 

Thanks!

[md13ffhguy]

It might depend on the temperature - i.e. How hard would the AC have to work? I seem to do pretty well with the windows down, even when it's in the 90s. However, I know a lot of people would never do that.

[FusionHemi]

Yeah that is definitely too hot. It was low 80s today and while moving it wasn't bad but sitting at the lights got a little uncomfortable.

[lolder]

A good rule of thumb is to put all the windows down for a few minutes in a heat soaked car and then use the AC. At higher speeds open window drag is significant.

[BoatDrinksQ5]

I think there have been some tests on this - I think the break-even point was around 50 or 55mph.

 

I suppose the outside conditions and interior temperature set-point, along with dynamics of each car effects that greatly.

Edited October 27, 2015 by BoatDrinksQ5

[Hybrider]

In my FFH, my experience during city driving at speeds of up to 50 MPH has been that having the A/C on drops my MPGs much more than having 3 of the windows open about 2-3 inches each.

[lolder]

If you have a moonroof, putting the back up and opening a rear window a crack is good in moderate temperatures.

[FusionHemi]

If you have a moonroof, putting the back up and opening a rear window a crack is good in moderate temperatures.

Yeah I was playing with that this evening.