The correct response is:
Incandescent bulbs produce other forms of energy, too, including heat.
Compact fluorescent bulbs (CFLs) are more energy-efficient than incandescent bulbs because they convert a larger portion of the electrical energy they consume into visible light rather than heat. Incandescent bulbs waste a significant amount of energy as heat, while CFLs utilize the energy more effectively for producing light. Hence, CFLs can produce the same amount of light (lumens) as incandescent bulbs while using less power (watts).