# Which gives better fuel efficiency...

**URL:** <https://boards.straightdope.com/t/which-gives-better-fuel-efficiency/194202>\
**Category:** Factual Questions\
**Created:** [August 10, 2003, 3:38pm UTC](https://boards.straightdope.com/t/which-gives-better-fuel-efficiency/194202 "2003-08-10T15:38:22Z")\
**Posts on this page:** 5\
**Page:** 1

<div class="post-metadata">

**Author:** ![Wallenstein](https://avatars.discourse-cdn.com/v4/letter/w/b5a626/32.png) [@Wallenstein](https://boards.straightdope.com/u/Wallenstein)\
**Post date:** [August 10, 2003, 3:38pm UTC](https://boards.straightdope.com/t/which-gives-better-fuel-efficiency/194202/1 "2003-08-10T15:38:22Z")

</div>

… driving using the air-con, or driving with my car windows open?

I have a small car (998cc Nissan Micra), so using the air-conitioning causes a very noticable increase in the rate of fuel consumption.

However, driving with the windows open surely messes up any aerodynamics my car has, and that too should increase fuel consumption.

Any ideas which method is more economic? I guess it depends a lot on how fast I’m going?

Thanks,

– e-logic

---

<div class="post-metadata">

**Author:** ![Bob55](https://avatars.discourse-cdn.com/v4/letter/b/e9c0ed/32.png) [@Bob55](https://boards.straightdope.com/u/Bob55)\
**Post date:** [August 10, 2003, 3:47pm UTC](https://boards.straightdope.com/t/which-gives-better-fuel-efficiency/194202/2 "2003-08-10T15:47:49Z")

</div>

Cecil wrote a column on this, and I think it’s in one of his books. I know for a fact I’ve read it online, but just can’t find it in the archive. If I recall, he said he actually tried it one day on a drive, and figured that there was no noticable difference in fuel efficiency with the windows up or down. I’ll keep searching the archives for you though.

---

<div class="post-metadata">

**Author:** ![Bob55](https://avatars.discourse-cdn.com/v4/letter/b/e9c0ed/32.png) [@Bob55](https://boards.straightdope.com/u/Bob55)\
**Post date:** [August 10, 2003, 3:52pm UTC](https://boards.straightdope.com/t/which-gives-better-fuel-efficiency/194202/3 "2003-08-10T15:52:31Z")

</div>

Well [this site](http://adsforcars.com/straight0531.html) disagrees with what I just said, saying:

> [@](#):
>
> it was slightly more economical to drive with the windows up using the air conditioning. In city-type driving, it is always more economical to drive with the windows down due to the reduced effect of wind resistance. Most of the air-conditioning systems today use a cycling or a variable compressor. Many years ago, air-conditioning compressors consumed more engine power than they do today and also operated all the time.

Still can’t find Cecil’s report ☹

---

<div class="post-metadata">

**Author:** ![hawthorne](https://avatars.discourse-cdn.com/v4/letter/h/c89c15/32.png) [@hawthorne](https://boards.straightdope.com/u/hawthorne)\
**Post date:** [August 10, 2003, 4:17pm UTC](https://boards.straightdope.com/t/which-gives-better-fuel-efficiency/194202/4 "2003-08-10T16:17:20Z")

</div>

Here you go Bob55 (I searched for “windows up”):  
[What gets the better gas mileage: windows up, AC on, or windows down, AC off?](http://www.straightdope.com/classics/a2_393.html)

---

<div class="post-metadata">

**Author:** ![Wallenstein](https://avatars.discourse-cdn.com/v4/letter/w/b5a626/32.png) [@Wallenstein](https://boards.straightdope.com/u/Wallenstein)\
**Post date:** [August 10, 2003, 5:25pm UTC](https://boards.straightdope.com/t/which-gives-better-fuel-efficiency/194202/5 "2003-08-10T17:25:45Z")

</div>

Thanks lads - much appreciated 🙂