Is using the car *fan alone* (not A/C) better than driving with windows down? Does it use less petrol to run the car fan with the air conditioning off and windows up, or to have the window down with the car fan off? I already know that it is better to drive with the windows down except above speeds of 80KM/H, but what about if you are just using the car fan with A/C off?

Additional Details

1 month ago

I would also like to know if, as suggested, fan alone is better than windows down, is this at any car speed and any fan speed? If not, please nominate particular speeds where it would be better to do one or the other (car speed, fan speed, or windows down).

Best Answer

At highway speeds, these are most efficient options (best to worst):

1. Windows up, AC and Fan off.
2. Windows up, Fan on.
3. Windows up, AC and Fan on.
4. Windows open, AC and fan off.

At city speeds

1. Windows up, AC and Fan Off
2. Windows up, fan on
3. Windows open
4. Windows up AC and Fan on.

The AC compressor is what uses the majority of the petrol in your car, not the fan. The differences between the configurations in savings are pretty minor (maybe 2% - 5% difference in fuel use), but every little bit helps.

Asker's Rating:

Pretty thorough, but mention of a source would have been good.

Other Answers (4)

• The car fan uses very little power compared to the A/C so I%26#039;m pretty sure using the fan with windows closed will be more economical than no fan and the windows open.
  Of course it will probably be more pleasant to drive with the windows down but it will certainly use more fuel, especially on the highway.
• The last answerer did not read the question correctly.
  
  But anywho, I hardly think that%26#039;d sap power from the engine, well it would but I mean, we%26#039;re talking small here. The engine turns a fan for the radiator, and I don%26#039;t think that saps power.
• I think it saps the car energy but not much, %26#039;though it is better to wind down your windows but once in a while, it is necessary you have some fun!
• I think they did a mythbusters on this. Yes the AC saps your energy, but its always good to run it once in a while.