Is it most economical to have the windows open or the air con on?

In the summer, is it most economical to have the windows open or the air con on? I have a 2008 Ford Ka.

Asked on 17 June 2010 by Mick Smith

Answered by Honest John
In 30 limits and especially in traffic jams, widows open. Out on the open road at speed, windows closed and air con on.
Similar questions
Which has the least effect on fuel consumption: having the air conditioning on or opening a window?
I have been driving Honda Civics for about the last 15 years or so and have loved them. My current Civic is well overdue for a change. But what has Honda done to the rear window? I positively hate it and...
I know that a/c reduces fuel economy, but what would achieve better fuel economy - to set a higher temperature and higher fan speed or to set a lower temperature and lower fan speed?
Related models
Easy to drive and economical. Handles better than Fiat 500. More room in rear than the Fiat.
 

Value my car

Save £75 on Warranty using code HJ75

with MotorEasy

Get a warranty quote

Save 12% on GAP Insurance

Use HJ21 to save on an ALA policy

See offer