Not really. When the air con is running the car uses a noticeable more amount of fuel. Its a waste if you dont need it.
Thanks for your help tho at least i no when it should and shouldnt be working now cheers 
True about the fuel. And theres a power loss.
If its kept on auto (especially at this time of year) and its warmer in the car than you have it set at, then justopen the window for a min the A/C wont kick in.
Especially at this time of year
