Wasted heat, or is it?

Traditional incandescent light bulbs work by passing an electric current through a tungsten filament, the resistance of the filament causes it to get very hot and as a by product light is given off.

This of course means that incandescent bulbs waste most of the energy they use as heat. Energy efficient light bulbs are obviously the better choice in this respect, but I have some reservations about the accuracy of the calculated savings.

In the summer when you don't need to heat your home the heat energy is indeed wasted (and may even add to the costs of air conditioning), but in the winter that heat is no longer wasted, it is in fact heating your home for you. My concern is that this fact is often overlooked when people calculate the 'savings' of a energy efficient bulb.