Fuel consumption

[davidprout]

Does my car's fuel consumption deteriorate when I use electrical components. e.g. Heater, air conditioning, lights etc.

[boncey]

I believe that it does. In some cars you may see the revs go up slightly if you turn on the heater for example, this is most noticable when your car is stopped. I have been known to "run silent" when I'm almost out of fuel by turning off the heater and radio, just in case.

[GeorgeR]

Yes it will, but not immediately and not at all significantly. The electricity required will be taken from the battery, which will eventually cause the automatic charging rate to be increased, to replenish it. This charge is provided by the alternator, which is driven by the engine, via the fan belt. The more charge it is required to deliver, the more drain it imposes on the engine. Hence, the more fuel that will be demanded by the engine.

[barnetboy]

absolutely...air conditioning can sap upto 2% of an engines power when turned on, it might not sound like much, but over a hundred mile stretch, that's two miles worth of fuel sapped...now modern cars can cost as little as 50p per mile to run...thats a quid for every hundred miles traveled..multiply that by your milage and you'll see you're wasting a hell of a lot of money!!!

[Typo]

Whilst air conditioning does indeed consume a not insignificant amount of power, you'll probably find that the drag caused by the opening of a window is worse. How much power is consumed by the average car air conditioning system? I think a domestic refrigerator or freezer might consume about 0.2 horsepower, which doesn't sound a lot.