Even Worse Fuel Consumption

[J50OBY]

I knew that Air Con worsened fuel consumption but I didn't know by how much.
So I did a test. At 78 mph (true) over 250 miles on autoroute without Air Con I got 32.7 mpg.
With Air Con I only managed 28.8 mpg - a 12% hit.
Does that sound about right?

 

[Arkatee]

Doesn't sound right. I get 40mpg Bristol to Copenhagen with Air Con.

 

[Andyk]

I get around 40 on motorway runs with aircon on, but tend to sit at 70 mph.

 

[Robsyuk]

I don't even get 22mpg