Cause: Incandescent bulbs give off more heat than light, so they must be warming up the house.

Effect: It is hard to see this logic as anything but a weak excuse for holding on to the Edison bulbs rather than switching to CFL and LED lighting. In fact, one German entrepreneur is marketing incandescent bulbs as "heat balls" to skirt EU laws against the old-style bulbs. However, I doubt he is keeping cozy this winter simply by sleeping with the lights on.