28/07/2026
An incandescent light bulb gives off 90% of its energy as heat, not light. A compact fluorescent light (CFL) converts 85% of its energy to light, and a light-emitting diode (LED) light is even better, putting out 90% of the energy it uses as light. Switching to a more efficient bulb will make for a cooler room and lower your energy bills too. If you do use incandescents, turn them off well before bedtime for a cooler room.