Ballasts: 9 of 21

The ballast input watts indicates the power consumed by the ballast when it is operating lamps. For example, a 4-lamp electronic ballast may be listed as having input watts = 101.

This might include 4 lamps operated at 24 watts each (=96 watts) plus 5 watts of ballast losses. So, a 4-lamp fixture with this ballast will be using 101 watts.

With HID and Halogen/Incandescent lamps the lamp wattage indicates the power consumed by the lamp. With Linear fluorescent lamps the F32 designation merely means that for photometry the lamp was operated at 32 watts. In a fixture the lamps are hardly ever operated at 32 watts; in fact they may be operated anywhere between 22 watts and 38 watts depending on the ballast that is connected.

You almost never find out the exact wattage the lamp is operated at, you merely know the ballast input watts for the ballast.