keeps me in a job testing components that we manufacture and supply (8 million compressors in europe alone last year).

once you've had it, you wouldn't be without it again. and it doesn't have to be the hottest country to get a benefit from it. even england at 20 degrees with sunshine can make the car unbearably hot if you keep your windows closed.

as for fuel consumption increasing when using it. compared to not using it, of course it does, but when you compare it to driving down the motorway at 70mph with all the windows open it doesn't. it depends on the speed and driving conditions, and i know cos we've tested it in our climatic wind tunnel.

what you also have to consider is that you can have the air in recirculating mode with a/c, so although the a/c has to work hard to bring down the cabin temperature initially, it then doesn't have to do much to maintain it.

unfortunately, old ford's use old technology fixed displacement compressors. these are switched on and off with an electromagnetic clutch as and when the needed. these have a negative effect on driving pleasure as they can often be felt cutting in and out when cruising. newer cars tend to have variable displacement compressors that automatically adjust to the heat load.

by the way, the most power required from the engine to drive an a/c compressor will be around 8 bhp, but that is in the most severe conditions of death valley. the most in europe will be around 5bhp, but then only at the beginning. if you miss this 5bhp on an escort cosworth i would be surprised. of course, the condenser fans also require some power, as does the blower in the car, but not that much. and don't forget that driving with windows down at any kind of speed effectively robs power by increasing drag.