Engine revs up when heater is switched on.

Noticed my car revving a bit more than usual when I turn on the heater, is this normal?

Think it needs tuning as car shakes ever so slightly when stopped and engine running. 

If the aircon button has been depressed when the fan is switched on, this is entirely normal; the ecu compensates for the extra load from the aircon compressor.

 I have no aircon in my car, it was taken out at some point:(.

But I will check the button, it might have been pressed in by accident. hee hee